AR-Stoner 6.5 Grendel barrel short chambered.

[SMM123]

I get your frustration. To try to explain, if chambers are designed to shoot short blunt bullets at the max OAL 2.26 the freebore will be long so those bullets aren't jammed into the lands. If long bullets like the Lapua Scenar 123gr is loaded to 2.26 the jump to the lands will be .100" or more and accuracy will suffer. In factory produced firearms like Remington or Winchester the chamber designs are one size fits all so all bullets work at the max OAL, accuracy isn't great but most can't tell the difference anyway. In more custom rifles the chamber designs are usually designed for better accuracy and usually with a slow twist barrel the longer high BC bullets are used so the throat is designed shorter to shoot those high BC bullets better. Around 2006 it seems everyone was shooting the Lapua 123 in the Grendel, it works fine. If some one wants to handload a light Speer TNT in the Grendel it must be loaded to a shorter OAL length to keep it out of the lands. That is just part of handloading. Any ammo company loading for the Grendel should know where the lands are and should know to load the bullets to keep them out of the lands. That would be up to the individual handloading to know the same.

I am only concerned about factory ammunition. THAT is where it MUST be right. This is all to which I was referring. If a handloader screws it up, that is his/her fault and has nothing whatsoever to do with the fact that the built rifle should work without issues using factory ammunition. No measuring, no special tools, no bullet/chamber special nomenclature knowledge.

Load ammo from factory box, aim rifle, disconnect safety, squeeze trigger, BOOM! That is RIGHT. If that does not happen, it is wrong.

[woohoo]

I am only concerned about factory ammunition. THAT is where it MUST be right. This is all to which I was referring. If a handloader screws it up, that is his/her fault and has nothing whatsoever to do with the fact that the built rifle should work without issues using factory ammunition. No measuring, no special tools, no bullet/chamber special nomenclature knowledge.

Load ammo from factory box, aim rifle, disconnect safety, squeeze trigger, BOOM! That is RIGHT. If that does not happen, it is wrong.

I agree fully, the company should load all ammo to keep the bullets out of the lands.

[JASmith]

I agree fully, the company should load all ammo to keep the bullets out of the lands.

Concur fully!! And the ammunition manufacturers accomplish that for rifles built to spec.

The barrel maker also has the responsibility to make sure that standard factory ammunition will fit and function safely.

...of course this is the true center of a debate that should not have occurred, much less gone on for 35 pages.

[BjornF16]

I have been building AR's of various calibers for years. I purchase components from vendors of all sorts - high quality, average quality, and production quality, brand names, and names I have never heard before. In all my years, I have thrown together the various components from different manufacturers and never once had a concern as to whether my rounds would chamber, fire, and extract properly, that is until I started with 6.5 Grendel.

Why is it that I can purchase AR-Stoner 300 AAC BLK, 5.56, 5.45x39, 7.62x39, and 9mm barrels (among other brands), and bolts from other sources, put them together and they just work, regardless of who's factory ammo I load into them; No measuring, no special tools, no 30+ page forum posts about why it won't work; but then you get a Grendel barrel and all hell breaks lose?

My first AR build was a Grendel. I've built two Grendel AR15s and one Grendel bolt. I haven't had any issues. Both of the AR barrels are Satern (cut rifled, hand lapped).

As you have ascertained in reading the 34 pages of "hell", the issue is the Liberty barrel (AR Stoner and possibly Brownell's). It does look as if it is a matter of a "rough throat". It is interesting that Satern also produces the Liberty barrels...I look forward to Satern's assessment of their Liberty barrels that exhibit the issue.

There is no doubt the Grendel is not the typical chamber design...perhaps the compound throat lends itself to these issues if not lapped/polished.

I seriously doubt that the issue is with Hornady factory ammo. I don't believe the issue exists with any other barrel brand.

[Kikn]

I have somehow refrained from posting on this....until now.

I had an early version of an AA barrell and still shoot it to this day.

I had issues unbeknownst to me after going to the range a few times. I had never manually ejected a round. I would just shoot out what was in the magazine and go about my business.

Fast forward to my first hunting trip. I go out and blast a double hog kill from about 50 yards. Life is good until I try and eject the round manually. To my dismay it would not eject. The round at times would get so stuck that while doing a mortar ejection it would pull the bullet out of the casing.

I continued to shoot for many rounds somewhere between 200-400 I would guess and the issue never resolved. Reluctantly I had contacted Bill A. with my issue after contacting the company I had bought it from at the gun show Bill took my rifle in and told me that they had to ream out the throat as it was to tight. Since I've gotten the rifle back I have not had any issues. There wasn't any issue with pressure on factory hornady loads just couldn't eject the rounds manually...

my suggestion would be to shoot the gun see how it performs. With factory ammo. And test and find out if you can eject rounds manually or not after firing a round or two.

[dmsims21]

The guess tight throats happen. The key is that AA admitted it and fixed it.
One can infer that the design intention is that unfired rounds should eject freely.

[Tedward]

Just like he said, it was a tight throat and Bill had to ream it out. He should have made these measurment changes then gave it to SAAMI.
Steve said he knows the issue and might be making a modified Grendel Reamer with the wider throat. So it's not wrong, it's the way Bill A submitted it to SAAMI.

[LRRPF52]

Just like he said, it was a tight throat and Bill had to ream it out. He should have made these measurment changes then gave it to SAAMI.
Steve said he knows the issue and might be making a modified Grendel Reamer with the wider throat. So it's not wrong, it's the way Bill A submitted it to SAAMI.

Bill A. didn't submit the Grendel to SAAMI, Hornady did. We haven't had 35-page threads about the chamber up until now. The Grendel is meant to have a compound throat, but not to the point that a projectile is jammed so tight that it won't extract. I don't have any of the barrels in front of me, so I can't measure and test with a dummy cartridge myself, but I suspect that using a case gauge, as soon as one transitions into the throat and feels resistance, that could be interpreted as a "short throat".

A dummy cartridge will show whether the compound throat engagement is too tight or not. I have been going through all the Lilja barrels I have, and they are all fine. My 2.275" A-MAX drops in and out like butter, and a 123gr SST loaded to 2.253" easy extracted, although it did have slight engagement with the throat. I sized it down to 2.245", and it drops out with a tap of the barrel, so there is no way either the 2.253" or 2.245" loads with the 123gr SST would hard extract.

I would suggest that anyone with their Liberty barrel perform this test with the bullet they are using, referencing a reloading handbook for that bullet first, since many of the projectiles I saw mentioned earlier in the thread should be loaded to 2.200" anyway, like the 100gr Nosler BT. I'm guessing that most of the barrels are fine, but I can't verify that without them front of me. The Satern barrel I have behaves just like these new Lilja's and my AA, so I only see consistency on this end, and we're talking about 20 different barrels, from 3 different manufacturers, from 3 totally different regions in the US, who somehow all got it right.

+1

Seriously, the Signal to Noise Ratio on this thread is horrific! Just guessing, but there is likely less than two pages of actual facts and findings.

I agree. The signal to noise ratio has always been very low on the Grendel Forum, up until recently. Some of you need to read more, study the subject at hand, dive into some technical resources, and ask some basic questions about logic before posting, and I genuinely mean that in the most polite way possible.

[dmsims21]

Just like he said, it was a tight throat and Bill had to ream it out. He should have made these measurment changes then gave it to SAAMI.
Steve said he knows the issue and might be making a modified Grendel Reamer with the wider throat. So it's not wrong, it's the way Bill A submitted it to SAAMI.

That doesn't prove the design is wrong. It may, or it may not. Another explanation is that the throat was not in spec or it was a little rough.
The chamber design is probably difficult to make reamers for, and difficult to inspect. You can't just put some calipers on the throat area and measure. You have to measure at a specific location along the axis of the reamer.

[NugginFutz]

Would someone with one of the problem barrels PLEASE take a cast of the chamber and have a qualified gunsmith measure the resulting cast? That would give this thread even more energy to debate the issue. Even then, I doubt it would satisfy some of the people on this thread who are seemingly intent on defending a barrel that can't chamber factory ammo.

Never before have I read where a SAAMI spec'd barrel that could not chamber factory ammo was given a pass. I'm having a great deal of difficulty understanding why this case is different.

With all the back and forth on what is SAAMI and what isn't, I really think the main point keeps getting buried in the noise.

"Why should a customer be told the product they bought is acceptable, when it won't do what it was ostensibly designed to do?" I see a couple of customers here, who are still left holding the bag.

[dmsims21]

Would someone with one of the problem barrels PLEASE take a cast of the chamber and have a qualified gunsmith measure the resulting cast? That would give this thread even more energy to debate the issue. Even then, I doubt it would satisfy some of the people on this thread who are seemingly intent on defending a barrel that can't chamber factory ammo.

Never before have I read where a SAAMI spec'd barrel that could not chamber factory ammo was given a pass. I'm having a great deal of difficulty understanding why this case is different.

With all the back and forth on what is SAAMI and what isn't, I really think the main point keeps getting buried in the noise.

"Why should a customer be told the product they bought is acceptable, when it won't do what it was ostensibly designed to do?" I see a couple of customers here, who are still left holding the bag.

+1

Especially on the chamber cast. It would also be cool to see a chamber cast of a top end barrel.

[WildBill3/75]

Just tested out a dummy round I had made for my old barrel that I was getting 2.271 to the point of resistance...This Dummy is set at 2.261

Last night I measured to the point of resistance in my Satern cut rifle barrel @ 2.230. I witnessed superficial land marks with the 2.245 factory 123gr amax ammo, needed a magnifying glass.

This 2.261 dummy most defiantly got jammed in the lands.

[Tedward]

I shot 5 new barrels today before I had to leave for the day. All of the uppers with Liberty Barrels fired and extracted without an issue, NONE would chamber a round all the way in so the bolt would lock by hand as being described here.. It was apparently feeling resistance.

So I put the uppers on my lower, chamber it with the bolt using the buffer spring and they all fired with the factory Hornady ammo. 2 rounds, BOOM, BOOM, cycled fine and bolt lock back on the last round for each upper.

So weather is leaves marks or not I don't know because they shot out the end of the barrel, it chambers and fires factory ammo fine.

This doesn't mean it isn't rubbing as your describing. Is it wrong? I don't know but it works.

[NugginFutz]

In other words, your factory ammo was Jammed into the Lands.

Almost without exception, Ted, the conventional wisdom is to provide a "Jump" of some measure, to both achieve the best accuracy and to avoid pressure problems. Only experienced reloaders should load ammo that is jammed into the lands, and they only do so, after carefully working up their loads to avoid pressure signs. Just because it goes Boom, doesn't mean you have a good situation.

[Sputnik]

What other unneeded stresses are caused with that situation? Will that be likely to cause late or early unlocking, extractor malfunctions, or more easily broken bolts, etc?

[NugginFutz]

Sputnik - when it comes to gas operated auto-loaders, extreme high pressures can cause late unlocking, case heads being ripped off, fail to extract, etc.

In general, a lot of bench shooters will load long, for increased accuracy, but these are the exception. Hunting rifles and AR's generally do not do so, as the results of being jammed are difficult to extract rounds, as well as the very undesirable occasion of a bullet being left in the throat, and an action full of powder.

Just plain bad juju for most AR type weapons, and certainly not for the unwitting / unwilling.

[dammitman]

so whats the final solution to all this? i just ran on to this thread and i have a barrel from this i ordered direct from satern/liberty. i have a bolt stripped and hold the barrel pointing up and it wont allow the factory hornady sst or amax to go far enough to close. now the go/ and nogo gauges show things right. so i know the throat is just shorter than factory ammo will allow. i think i may just figure out how to use this short throat to my advantage and build a ammo specific rifle utilizing the short throat,,,,,,,,,,,(i see more broken bolts commin!)

[XcountryRider]

I shot 5 new barrels today before I had to leave for the day. All of the uppers with Liberty Barrels fired and extracted without an issue, NONE would chamber a round all the way in so the bolt would lock by hand as being described here.. It was apparently feeling resistance.

So I put the uppers on my lower, chamber it with the bolt using the buffer spring and they all fired with the factory Hornady ammo. 2 rounds, BOOM, BOOM, cycled fine and bolt lock back on the last round for each upper.

So weather is leaves marks or not I don't know because they shot out the end of the barrel, it chambers and fires factory ammo fine.

This doesn't mean it isn't rubbing as your describing. Is it wrong? I don't know but it works.

After you break them in you can load longer out. This thing is a big panic about nothing. I'm getting nice groups at 200 yards with my barrel. I hope satern changes nothing.

[Tedward]

Sputnik - when it comes to gas operated auto-loaders, extreme high pressures can cause late unlocking, case heads being ripped off, fail to extract, etc.

In general, a lot of bench shooters will load long, for increased accuracy, but these are the exception. Hunting rifles and AR's generally do not do so, as the results of being jammed are difficult to extract rounds, as well as the very undesirable occasion of a bullet being left in the throat, and an action full of powder.

Just plain bad juju for most AR type weapons, and certainly not for the unwitting / unwilling.

No pressure signs at all. I guess the bullet will hit the lands sooner or later when shot. I will see if after a few rounds and the barrel breaks if it opens up some so the round will go in and out easier. I'll see.

[Tedward]

After you break them in you can load longer out. This thing is a big panic about nothing. I'm getting nice groups at 200 yards with my barrel. I hope satern changes nothing.

you beat me to the response it and I agree.