Grendel II chamber

[Walter]

Go there nugginfutz. The throat is part of the chamber. Take a look at the print. How could it not be. SAMMI is there to make sure the cartridge will fit in the chamber.

[rickOshay]

The "Confused and Misrepresenting" will not claim the Grendel II is a SAAMI 6.5 Grendel. They are now using a nonsensical term of "SAAMI Compliant". Sort of like saying "almost pregnant".

If the throat does not have a 0.5 degree taper, it's not a SAAMI 6.5 Grendel.

They are widely claiming that the taper is what is wrong with the Grendel, hence the Grendel II name to draw comparison to the 6.8 SPC saga. The implication is that the SAAMI chamber is bad and needs fixing. Pure marketing hype and internet hysteria.

The Grendel II is an answer to a question not being asked. Just another way to try to damage the image of the SAAMI 6.5 Grendel - which is the ultimate goal of these folks.

[rickOshay]

This recent drama over throat dimensions has been, in my opinion, Much Ado about Nothing.

The recent debates have been over various opinions about the dimensions of the throat of chambers the 6.5 Grendel. I really don't want to rehash the arguments about throat dimensions. I just want to try to put things into some perspective. So I am providing an EXAMPLE of what that might look like.

The recent drama has resulted in the commercial production of yet another Grendel variant - the Grendel II. My understanding is that the driver behind it was to have a longer throat than the SAAMI 6.5 Grendel in order to seat long-for-caliber bullets farther out of the case.

Now there has also been a debate as to whether this new variant is an answer to a question not being asked, because the SAAMI 6.5 Grendel can handle bullets up to the 156 gr Lapua Mega. This was done by Lapua, one of the contributors to the development of the SAAMI 6.5 Grendel. Moreover, the primary medium sized game that the Grendel is well suited to take can be easily handled with projectiles weighing 125 gr or less, and fit nicely into the 6.5 Grendel compound throat. The need for these large projectiles really is questionable. What advantage to they bring?

But the idea of getting more powder in the case for the long bullets is an intriguing one. So how much more powder is it really?

A recent post (#412) by Mark at Precision Firearms recounting a discussion with Dave Kiff at PTG says the Grendel II is the same as the .264 LBC-AR. (http://www.65grendel.com/forum/showthrea...rns/page42) except having a neck diameter of 0.300”.

And several people have reported that you can seat bullet out 0.1" farther - e.g. 2.350" vs. 2.250"

If you assume the case is already completely full, what does moving the bullet 0.1" further out really get you in the way of more powder?

Well, if you evasion the bullet moving forward 0.1", then a void would be created behind the bullet with the dimensions of 0.1" long by 0.264" in diameter (for a flat base bullet to keep it simple, boat tails would actually be much less). The volume of that void would be calculated by:
volume = pi x radius^2 x height
volume = 3.14 x 0.132^2 x 0.1
volume = 0.00547 cubic inches

How much powder will fill the void of that volume?

The density of CFE 223 is 15.957 grains per 1 cc.
- 1 cubic inch is 16.387 cc's.
- so 0.00547 cu in is equal to 0.089 cc's

So the amount of CFE 223 that would fill 0.089 cc's is 1.4 grains (15.957 x 0.089).

So the longer chamber would enable one to add 1.4 grains more per case.

What does that get you? About 30 - 50 feet per second higher velocity depending on the bullet.

What does that mean to the hunter? About 30 yards longer hunting reach. Hunting reach is here defined as the distance at which the bullet drops below is minimum recommended velocity for proper expansion.

YES - there is measurable advantage for a subset of 0.264 projectiles available to the reloader if a longer chamber is used.

I will put forth that the average hunter will not be able to see any real world advantage here.

And I'll repeat - these longer bullets are not needed to take most game folks are going after (see 6.5 Grendel Reloading Handbook Volume 2 and http://shootersnotes.com)

Again, so much drama and energy spent on negligible benefit.

[Overwatcher]

I still at a loss as to why Satern has created this hysteria.Make a friggin 6.5 saami spec Grendel and be done with it.I have one of their 20" barrels and its a machining masterpiece.Again excuse my ignorance for even bringing this up.So honestly where does our alligence for Satern lie as a horde? Possibly sending a "horde" letter if it hasn't been done yet to solve the shlit show.A lot of pull comes from members and internet forums for a hell of a lot of gun related product.Ignore if an attempt has been made.
We have extreme cases on both sides of the fence,but honestly the whole deal makes me want to go drink myself stupid.

[hidesert cowboy]

I disagree that the exact dimensions of the throat are part of the spec. When you have a custom rifle built and if the gunsmith is a good one they always want to chamber to a dummy round. this is so they can set the throat. The throat is cut in a separate process. lets go pull a ruger, remington and tikka rifle off the shelf, in 308 winchester. would you expect there to be the exact or close measurement base to lands on those different rifles off the shelf?? with the talk that is around here about sammi this and that why even bother to measure the others?!?!

here is a link to the reamers gre tan rifles has on hand
http://www.gretanrifles.com/reamers.jsf

notice that all calibers have a neck diameter AND a throater you can spec in particular look at 6mm there are 3 different throats you can spec, with 6.5 there are 4 different choices in throat you can spec. Not all gunsmiths do it this way, for example a company like GAP rifles you must send or use one of their reamers which doesn't allow the neck and throat options, its fixed to whatever reamer that is because they do the whole thing in one process. things aren't always what they seem.

[NugginFutz]

Well, for starters, you are creating an apples and oranges argument. There is no direct comparison between Custom rifles and SAAMI spec'd rifles. By their very nature, custom chambers, as you observed, have no hard and fast standards or specifications. A SAAMI spec'd chamber on the other hand, is designated such, so that ammunition manufacturers and barrel makers can produce compatible products. You are free to disagree, but the fact is that the specification for the Grendel chamber, as shown in the drawings submitted to SAAMI for approval, do extend to the throat.

When you take the discussion to the realm of gunsmiths, and custom builders, it is a design agreed upon between the customer and the builder. At that point, both parties come to an agreement on what the chamber will look like. Stock, factory chambers, on the other hand, allow the average consumer the comfort of knowing that the barrel will successfully chamber off the shelf ammunition marked for that chambering.

It really doesn't get any simpler than this.

[rickOshay]

I disagree that the exact dimensions of the throat are part of the spec.

Which part of this drawing do you think is not part of the spec?

[/IMG]

[LRRPF52]

I disagree that the exact dimensions of the throat are part of the spec. When you have a custom rifle built and if the gunsmith is a good one they always want to chamber to a dummy round. this is so they can set the throat. The throat is cut in a separate process. lets go pull a ruger, remington and tikka rifle off the shelf, in 308 winchester. would you expect there to be the exact or close measurement base to lands on those different rifles off the shelf?? with the talk that is around here about sammi this and that why even bother to measure the others?!?!

here is a link to the reamers gre tan rifles has on hand
http://www.gretanrifles.com/reamers.jsf

notice that all calibers have a neck diameter AND a throater you can spec in particular look at 6mm there are 3 different throats you can spec, with 6.5 there are 4 different choices in throat you can spec. Not all gunsmiths do it this way, for example a company like GAP rifles you must send or use one of their reamers which doesn't allow the neck and throat options, its fixed to whatever reamer that is because they do the whole thing in one process. things aren't always what they seem.

I've had 2 rifles built by GAP, both AR10's, and I was asked each time which bullet I would be shooting. With the .308 Winchester, I told them the 155gr Scenar, and they cut the throat to that bullet. With my .260 Remington, I told them the 139gr Scenar, 142gr SMK, and 140gr VLD. They cut each throat to the specific bullet ogive shapes I was planning to shoot, and both of those rifles shoot those bullets amazingly well. They are custom rifles with custom throats optimized for gas gun magzine-fed COL.

The Grendel SAAMI chamber is not a custom chamber. It's meant to address various bullet shapes at lower operating pressures, where you can't rely on 60,000psi to slam a VLD into the lands quickly like the .260 Remington does, with corresponding barrel life and weapon weight considerations.

The Grendel chamber really does handle a wide variety of projectile shapes well in extensive testing, as well as the customer pool. No matter what I load in mine, it shoots them consistently into ~ 1 MOA. Some are .79 MOA, while others 1.2 MOA like the 129gr SST, which is known to not shoot well in a lot of different chambers, whereas the new 123gr SST shoots amazingly well after Hornady upgraded their bullet-making equipment and reduced the jacket variance significantly, starting with the A-MAX line.

A lot of this is about egos getting in the way of providing a superior product to the customer in my opinion. Different makers can't check their egos at the door when they go to work, so the customer pays the price for it. Little do they know that they are just recreating chambers that didn't work well with a wide variety of projectile shapes when the Grendel was being tested.

For anyone to claim that their chamber will shoot better than the Grendel indicates that they have done more testing than the company that brought it to market, after a very strenuous testing regimen before releasing it to the customer. From that point, credibility goes downhill quickly.

If you look at the comparison that rick0shay posted above, a 2.350" COL can't be loaded in magazines anyway, so a single-loaded projectile that already fits well within the SAAMI Grendel will give you 30-50fps more MV if you single load it to 2.350". Just another attempt by the detractors of the Grendel to try to drag it down. They have found useful idiots who will believe their negativity, and wallow around in the mud together-relationships built on goals of ruining a fine product, and pull in totally new people to the AR15/hunting market who don't know the background.

What I would say to those who don't know the characters involved and the chips they bear on their shoulders against the Grendel is this:

Just enjoy the cartridge. If you have a variant chamber, there will be several of the over 100 projectiles available for 6.5mm that you will find that shoot well in your rifle when hand-loaded. Several of the factory loads should shoot well also. Just demand that factory ammo will feed and function safely in your chamber if you plan to shoot factory ammunition, which is something the Grendel was meant to do from the start.

A lot of this has to do with the frustration people feel when not able to shoot in the winter, and that is changing now for many with Spring coming. I feel for those of you who have been screwed over out of the performance I have personally enjoyed with my Grendel since 2009, which included reliability and accuracy-no issues or complaints. That's what is hard for me to see going on, when I know the potential of the system.

[bwaites]

I disagree that the exact dimensions of the throat are part of the spec. When you have a custom rifle built and if the gunsmith is a good one they always want to chamber to a dummy round. this is so they can set the throat. The throat is cut in a separate process. lets go pull a ruger, remington and tikka rifle off the shelf, in 308 winchester. would you expect there to be the exact or close measurement base to lands on those different rifles off the shelf?? with the talk that is around here about sammi this and that why even bother to measure the others?!?!

here is a link to the reamers gre tan rifles has on hand
http://www.gretanrifles.com/reamers.jsf

notice that all calibers have a neck diameter AND a throater you can spec in particular look at 6mm there are 3 different throats you can spec, with 6.5 there are 4 different choices in throat you can spec. Not all gunsmiths do it this way, for example a company like GAP rifles you must send or use one of their reamers which doesn't allow the neck and throat options, its fixed to whatever reamer that is because they do the whole thing in one process. things aren't always what they seem.

You may disagree all you like, the facts are the facts. The SAAMI Grendel drawing specifies the compound throat, period. We aren't discussing custom .308 drawings, we are discussing a SAAMI specc'ed Grendel, and in that case, the throat is very specifically defined.

In the case of custom rifles, like my 7mm WSM, I spec'd the throat to shoot 180 Berger Hybrids and 180 Berger VLD's. The barrel maker gave me essentially the throat he would cut for VLD's, and because the Hybrids like to be further off the lands, I load them a little shorter and all is well.

But the Grendel is NOT a custom chamber, its a standard, SAAMI chamber. It should load every single factory round, just like a .308 rilfe from Ruger, Remington, Winchester, or anyone else will. Yes there may be slight variations from one manufacturer to another, but when was the last time someone posted that their new .308 wouldn't take factory ammo?

As I've posted elsewhere, I can load my heavy bullets out past mag length in my SAAMI chambers, without any issues.

[haustinv]

I have been sitting back awhile taking in all these discussions. So here's my two cents worth. I believe what the real topic here is ethics. Bill Alexander with help from Arne, Lapua etc. created the 6.5 Grendel. He had the forethought to trademark his creation so as to prevent bastardization of its design. Now it has been officially standardized by being accepted and defined by SAMMI. Anyone who is in business has the right to create and modify to their hearts content any product. That's the American way. If they feel they can produce a better mousetrap go for it. What I have a problem with is simple ethics. If you make a modification to something that has been officially standardized you no longer have the right to call your modification by the name of the original to imply compliance. Either you comply or you don't. You can however state that your modification is compatible but it must have a different name. Companies and individuals sue in court all the time for this abuse and they win on both ethical and legal grounds. My feeling is that this whole issue may be from some sort of bad blood, or competitive drive between individuals that are playing in this game. Remember there were licensing issues during the birth of this round. Also don't forget the free advertising that this situation is generating. You know the old advertiser's slogan publicity either good or bad doesn't matter because it's all good in the end. There could even be other issues that caused this mess that we will never know and really don't care about. What I can't stand is we the little people are the ones getting hurt by this. We now have to be suspect of products we buy because we don't know which side of this battle any manufacturer truly is on. I just wish people would go back to the simple moral and ethical behavior we came to expect of each other. But I digress. What should happen is simple, SAMMI and Bill should actively sue anyone who is claiming to make 6.5 Grendel and is really making a variant and not labeling it as a variant. I have no problem with someone thinking they can do it better or fill a need that the original doesn't. What problem I do have is their misrepresenting their new idea as the old idea. If a gunsmith wants to custom chamber a barrel for a customer mark the barrel 6.5 Grendel modified. If a manufacturer wants to make a different product guess what, you don't use the Grendel name in any way shape or form. Les Baer did it right. He is a man I can still have respect for. Those that break the rules for whatever reason have lost it.

[45r]

The throat on the Grendel has a very slight taper of .2644 down to .2617 for a distance of .1547 and then another very slight taper for a distance of .1088.
The 264LBC reamer and other type reamers like it the front leading edge is doing all the cutting for the most part and if it wears down a little it doesn't make much difference.
A lot longer length is cutting the throat on a Grendel reamer.
It wears down faster and with the taper being .0027 deep(that's less than .0014 on each side) it doesn't cut the throat long enough and you end up with a shorter than normal throat.
The compound throat should be perfectly centered to get the benefit of centering the bullet in the cone.
The 264LBC type reamers are a cheaper way to cut barrel chambers since they are more tolerant with wearing out and being centered in the bore.
Both types can be accurate.
The Grendel is better for 85 to 123 grain bullets.
The Grendel reamers should not be used when they get worn out if you want to avoid short throats.
Worn reamers leave burrs on the downwind side of the lands a take a 100 to 200 rounds to smooth out the roughness.
The chamber cast picture of the Precision Firearms barrel shows what the Grendel throat looks like when done right.
If all Grendel chambers were cut like that barrel we would be happy I think.

[JASmith]

I disagree that the exact dimensions of the throat are part of the spec. When you have a custom rifle built and if the gunsmith is a good one they always want to chamber to a dummy round. this is so they can set the throat. The throat is cut in a separate process. lets go pull a ruger, remington and tikka rifle off the shelf, in 308 winchester. would you expect there to be the exact or close measurement base to lands on those different rifles off the shelf?? with the talk that is around here about sammi this and that why even bother to measure the others?!?!here is a link to the reamers gre tan rifles has on hand
http://www.gretanrifles.com/reamers.jsf

notice that all calibers have a neck diameter AND a throater you can spec in particular look at 6mm there are 3 different throats you can spec, with 6.5 there are 4 different choices in throat you can spec. Not all gunsmiths do it this way, for example a company like GAP rifles you must send or use one of their reamers which doesn't allow the neck and throat options, its fixed to whatever reamer that is because they do the whole thing in one process. things aren't always what they seem.

There is a lot wrong with this post -- and it shows either serious ignorance on the part of the poster or deliberate falsification.

Go here for the SAAMI spec: http://www.65grendel.com/forum/showthrea...l-Drawings and you will see the throat is part of the specification.

Second, only some manufacturers use a separate throater. I have a reamer that does the complete chamber.

One problem with a separate throating operation is that one can get the throat off-center from the chamber, so not all barrel makers do that.

This poster has erroneously or falsely claimed that the throat is not part of the spec until he has become "blue in the throat." Is he a subscriber to the Goebbles doctrine that a lie repeated often enough becomes the truth?

[nincomp]

I have been away from the forum for a while and missed much of the bru-ha-ha about chamber issues. I know that people are rightfully upset about non-SAMMI chambers in their rifles. My question is : "How do they shoot." Are there any accuracy problems?

If this has already been answered, please send me the link.

[hidesert cowboy]

I've had 2 rifles built by GAP, both AR10's, and I was asked each time which bullet I would be shooting. With the .308 Winchester, I told them the 155gr Scenar, and they cut the throat to that bullet. With my .260 Remington, I told them the 139gr Scenar, 142gr SMK, and 140gr VLD. They cut each throat to the specific bullet ogive shapes I was planning to shoot, and both of those rifles shoot those bullets amazingly well. They are custom rifles with custom throats optimized for gas gun magzine-fed COL.

The Grendel SAAMI chamber is not a custom chamber. It's meant to address various bullet shapes at lower operating pressures, where you can't rely on 60,000psi to slam a VLD into the lands quickly like the .260 Remington does, with corresponding barrel life and weapon weight considerations.

The Grendel chamber really does handle a wide variety of projectile shapes well in extensive testing, as well as the customer pool. No matter what I load in mine, it shoots them consistently into ~ 1 MOA. Some are .79 MOA, while others 1.2 MOA like the 129gr SST, which is known to not shoot well in a lot of different chambers, whereas the new 123gr SST shoots amazingly well after Hornady upgraded their bullet-making equipment and reduced the jacket variance significantly, starting with the A-MAX line.

A lot of this is about egos getting in the way of providing a superior product to the customer in my opinion. Different makers can't check their egos at the door when they go to work, so the customer pays the price for it. Little do they know that they are just recreating chambers that didn't work well with a wide variety of projectile shapes when the Grendel was being tested.

For anyone to claim that their chamber will shoot better than the Grendel indicates that they have done more testing than the company that brought it to market, after a very strenuous testing regimen before releasing it to the customer. From that point, credibility goes downhill quickly.

If you look at the comparison that rick0shay posted above, a 2.350" COL can't be loaded in magazines anyway, so a single-loaded projectile that already fits well within the SAAMI Grendel will give you 30-50fps more MV if you single load it to 2.350". Just another attempt by the detractors of the Grendel to try to drag it down. They have found useful idiots who will believe their negativity, and wallow around in the mud together-relationships built on goals of ruining a fine product, and pull in totally new people to the AR15/hunting market who don't know the background.

What I would say to those who don't know the characters involved and the chips they bear on their shoulders against the Grendel is this:

Just enjoy the cartridge. If you have a variant chamber, there will be several of the over 100 projectiles available for 6.5mm that you will find that shoot well in your rifle when hand-loaded. Several of the factory loads should shoot well also. Just demand that factory ammo will feed and function safely in your chamber if you plan to shoot factory ammunition, which is something the Grendel was meant to do from the start.

A lot of this has to do with the frustration people feel when not able to shoot in the winter, and that is changing now for many with Spring coming. I feel for those of you who have been screwed over out of the performance I have personally enjoyed with my Grendel since 2009, which included reliability and accuracy-no issues or complaints. That's what is hard for me to see going on, when I know the potential of the system.

so the gap rifles you mentioned you still call them 308 and 260 but the throats are specific to the bullets you shoot are they not still 308 and 260 chamberings?? I am not defending liberty barrels in fact I returned my barrel for a shilen. The problem centered around not being able to chamber factory ammo and that is a valid problem.

[WildBill3/75]

I have been away from the forum for a while and missed much of the bru-ha-ha about chamber issues. I know that people are rightfully upset about non-SAMMI chambers in their rifles. My question is : "How do they shoot." Are there any accuracy problems?

If this has already been answered, please send me the link.

Mine shoots exceptionally well. Sucks to be limited in COAL though. my chamber measures around 2.230 with 123amax....so there is no way around jamming.

If you are talking about "Grendel II" I dunno nor do I want to personally find out.....264 LBC chambers from what I've seen shoot pretty good.

[bwaites]

so the gap rifles you mentioned you still call them 308 and 260 but the throats are specific to the bullets you shoot are they not still 308 and 260 chamberings?? I am not defending liberty barrels in fact I returned my barrel for a shilen. The problem centered around not being able to chamber factory ammo and that is a valid problem.

The problem is that if you buy a FACTORY standard .308 Winchester (to use the full name), you expect that it will function with ANY factory ammunition, and it will. Has anyone here ever heard of a rifle that did not do so?

When you order custom rifles, the fact that it is being made specifically for you allows you to customize the barrel to what you WANT, not what the standard is.

If the standard accepts all .308, then your rifle may or may not do so. (I've seen a few AR10's that were so loose they almost could have accepted a 30-06, it seemed!)

Is it still a .308, yes. Is it still a .308 Winchester, NO, most emphatically NO. It won't accept all the factory .308 Winchester out there, thus it is not a .308 Winchester. Anyone who sold such a rifle WITHOUT specifying the difference would be liable for whatever happened when someone shoehorned a factory round in there and had a "kaboom".

It's not about defending anyone, its about the standard that is the 6.5 Grendel. That standard calls for a very specific compound throat. If the chamber does not have that throat it is not a 6.5 Grendel, it is a variant, just like a .223 Wylde chamber is a varianat on the .223, or any of the .308 tight necked variants that precision shooters like.

[nincomp]

For what its worth, several years ago, Clymer Tools and Reamers had the dimensions of numerous SAAMI and wildcat reamers online. They clearly labeled each print as SAAMI or as a variation such as Palma chamber, etc. At least the person buying the reamer knew what they were getting.

[LRRPF52]

so the gap rifles you mentioned you still call them 308 and 260 but the throats are specific to the bullets you shoot are they not still 308 and 260 chamberings?? I am not defending liberty barrels in fact I returned my barrel for a shilen. The problem centered around not being able to chamber factory ammo and that is a valid problem.

The .308 AR10 I had built pulls 168gr and 167gr factory ammo, and dumps powder everywhere. If you light one off, it craters or blows the primers.

The .260 Rem will never see a factory round if I have anything to say about it. I only fire hand-loaded ammunition through my .260 Remington. Every .260 Rem gas gun I've seen, as well as 6.5 Creedmoors, spit out brass with either:

* ejector swipes
* thrashed extractor rims
* Cratered primers
* flattened primers
* pierced primers

Here is what JP has posted on their website about the .260 Rem in a gas gun:

LRP-07™ rifles chambered in .260 Remington

[SIZE="3"]The LRP-07™ chambered in .260 Remington is designed primarily for the skilled hand loader[/SIZE], as there is little available in accurate factory .260 ammunition. Best accuracy is usually achieved at about 10% below recommended maximum load data in recognized loading manuals. Be aware that canister powders can vary significantly in burn rate from one lot to another and if you start a new lot of powder, it may be necessary to work up a new load. Do not assume that a “factory“ load for the .260 will perform satisfactorily in your LRP-07™ and assume that there is something wrong with the rifle if a particular ammo fails to function or exhibits high pressure signs. Available factory ammunition is designed for rifles with 1:9 twist barrels. We use a 1:8 twist barrel for improved accuracy with certain high BC-type projectiles. This may not be compatible with some factory loads. You may experience high pressure failures such as dropped primers and excessive bolt velocity resulting in extraction/ejection failures or even possible ruptured cases. If high-pressure signs are evident with any ammunition, discontinue use of that ammunition immediately.

Remember that gas-operated semi-automatic rifles in any caliber are much more ammo sensitive than manually operated rifles. You must find or load ammo that is compatible with the rifle, not expect that the rifle can be made compatible with the particular ammunition that you have chosen.

Every factory load I have shot through my 6.5 Grendel has fired, extracted, ejected, fed, and chambered correctly without these pressure signs, and it's fun to shoot. I honestly got into the Grendel thinking that I would only hand-load for it, but I ended up shooting a lot of factory ammunition in it from AA, Precision Firearms, and Hornady. What's not to like?

It makes it much easier for me to take it out shooting than my .260 Rem, which a very kind forum member has sent me an improved firing pin for to address primer piercing and cratering issues of the 60,000psi SAAMI .260 Rem. When you drive long bullets with slow powders and those pressures, and have a gap between the firing pin and the hole, the primer likes to fill in there. I've already bent & ruined at least 2 firing pin retaining pins with my .260 Remington AR10. Hopefully this new pin will solve the cratered primer issue.

When I describe the AR10's I have had custom built, I usually explain that the chambers were cut for specific bullet profiles. My .260 Rem will shoot all the bullets I had it throated for into very tight little clusters. Guess what? Trying to get the 140gr A-MAX to shoot that way has never worked, no matter what powder and combo I have tried. 139gr Scenars first 5rd group I ever shot looked like this:

[hm2 clark]

I Kinda understand that there is a difference between 5.56 and .223. Still, both chambers and bulllets will shoot in the guns I buy. Is that the kinda distenction we are drawing here?

[bwaites]

.223 chambers MAY exhibit high pressure signs with 5.56 ammo, which is loaded to higher pressures. The 5.56 chamber has significantly more leade than the .223, unless the .223 is a variant cut for long bullets. A .223 AR will often exhibit pressure signs with Black Hills 5.56 77gr ammo, for instance. Across the course shooters often have their ARs throated for longer bullets even than 77 grainers.