Liberty barrel evaluation and repair by Precision Firearms

[woohoo]

further-
The minimum 264LBC reamer has a .061" freebore, mid spec .080 and the largest .099".
The minimum Grendel SAAMI chamber has a .023" freebore. If the reamer is .001" larger in diameter than the minimum size the freebore is .080". If the reamer is the largest allowable spec in the Grendel the freebore is .137" That'll leave a ring.
Edited 2- I was off on the calculations, that's what I get for doing it on paper instead of a calculator. each .001" change in dia lengthens the freebore .057" using .5 degree as the angle

[Sputnik]

Whoa, gentlemen...please lighten it up. Sorry I caused this. How about this. Everybody is right. Also, Since this is really getting technical with all kinds of numbers and angles and such...Kinda space-like: Since I have a Neptune, and this Liberty comes from Satern (I know it is spelled differently), so I am going to name my chamber Uranus! Behold the ring around...

[woohoo]

Those lands appear to be in the area of 30:70 (land to groove) lands apx .050" wide. Compare that to the freebore(ring). I would shoot it and see how it does. The bullets shouldn't jam the lands so it shouldn't cause excessive pressure.
As for the compound throat, I think it would be pretty tough to tell the difference between a .5 and 1.5 degree slope with the naked eye.

[Sputnik]

Thanks, JASmith and Woohoo. I concur with the shoot it and see. The ring was not there before, and the "fix" seems to be remove the compound throat. So I guess that is what that looks like. The factory ammo removes easily, the lands no longer touch the projectile. Just hoping my ring doesn't work like a speed bump.

[45r]

My liberty barrel will let a 123 SST drop out of the chamber seated to 2.233 but will hold one seated to 2.245.
I think my barrel will be fine and drop a factory 123 SST round after some more shooting.
Some of the group buy barrels are probably OK.
I polished the throat a lot and now all I see is a few small scratches on a 123 sst when seated to factory spec and they seem to be made by a little roughness in the throat on one side.
That is probably what is holding the round from dropping at factory length.
My barrel shoots good and I must have got lucky.
A little JB's or Iosso on a patched 6 mm brush and some elbow grease might make some of the barrels work out and others might not see a need to change their chamber.

[SHORT-N-SASSY]

My liberty barrel will let a 123 SST drop out of the chamber seated to 2.233 but will hold one seated to 2.245.
I think my barrel will be fine and drop a factory 123 SST round after some more shooting.
Some of the group buy barrels are probably OK.
I polished the throat a lot and now all I see is a few small scratches on a 123 sst when seated to factory spec and they seem to be made by a little roughness in the throat on one side.
That is probably what is holding the round from dropping at factory length.
My barrel shoots good and I must have got lucky.
A little JB's or Iosso on a patched 6 mm brush and some elbow grease might make some of the barrels work out and others might not see a need to change their chamber.

45r,

I wish you good luck with your Liberty barrel.

I moments ago checked the MidwayUSA.com website: AR-Stoner Barrel and Bolt AR-15 6.5 Grendel Medium M4 Contour 1 in 8" Twist 16" Stainless Steel, Product #: 884877, "$256.19, Save $43.80 (14%)." http://www.midwayusa.com/product/884877/...less-steel

Compare today's price with their price on that same item reported in these Pages, on February 7, 2014, "$274.96, Save $25.03 (8%)."

I also checked the SaternMachining.com website to see if they've posted clarification re their short-throated barrels, as promised back on January 30, 2014: nothing yet http://saternmachining.com/

[NugginFutz]

One might think that they're trying to dump them before the word spreads.

[45r]

I've been shooting my upper with no problems.
Since my hand loads are within 12 thou of factory spec and Low ES over chrony I'm not too worried.
I've got some sub MOA groups and will try some more loads later on.
I'm sure some have got some barrels that are probably not close enough to work well but I think my barrel will shoot good enough for what I paid.

[LRRPF52]

If I had one of these barrels and it shot well, and digested factory Hornady without issue, I certainly would keep it and drive on.

[poli]

If I had one of these barrels and it shot well, and digested factory Hornady without issue, I certainly would keep it and drive on.

+1

[JASmith]

further-
The minimum 264LBC reamer has a .042" freebore, mid spec .080 and the largest .118".
The minimum Grendel SAAMI chamber has a .023" freebore. If the reamer is .001" larger in diameter than the minimum size the freebore is .137". If the reamer is the largest allowable spec in the Grendel the freebore is .251" That'll leave a ring.
Edited- I was off on the calculations, that's what I get for doing it on paper instead of a calculator. each .001" change in dia lengthens the freebore .114" using .5 degree as the angle

Our earlier posts suggest that we agree that we still need to see a bonafide SAAMI chamber compared to a "scraped" throat chamber.

The increase in freebore length can be no more than the .015 inches called out in the length tolerance by the SAAMI drawing. The .2644" dimension is allowed to float a bit because the drawing calls this out as a reference dimension.

The .5 degrees references the line you see on the drawing. If it were the included, or total, angle the call-out would have been different. This tells us that we need to account for the other side of the neck which also has a 0.5 degree taper, giving an included angle of 1 degree.

Applying this to a 1 mil diameter change results in a .057" change in where the ogive would touch the freebore for each change of nominal diameter of .001 inch.

These numbers also happen to get us closer to the reference dimension of .2644" at the start of the freebore.

[Tedward]

Whoa, gentlemen...please lighten it up. Sorry I caused this. How about this. Everybody is right. Also, Since this is really getting technical with all kinds of numbers and angles and such...Kinda space-like: Since I have a Neptune, and this Liberty comes from Satern (I know it is spelled differently), so I am going to name my chamber Uranus! Behold the ring around...

Can you post a picture of your PF barrel so there is a comparison?

[Sputnik]

My PF Neptune V barrel is installed onto a complete upper and I can not get my Iphone camera inside the receiver to get a picture of the chamber/throat/lands. But if it is a certified Grendel chamber we want for comparison, any chamber will do. I wish I would have thought to take a picture of the chamber before it was scraped. Maybe somebody else can post theirs, if they have a Liberty barrel that showed land marks on their ammo.

My main concern was with my 123 Amax and 123 SST factory ammo (2.245). It now goes in and comes out without resistance and with the bolt engaged in the lugs, no more land marks on my projectiles. I now feel I can shoot this without excessive pressure/safety issues.

[SHORT-N-SASSY]

. . . My main concern was with my 123 Amax and 123 SST factory ammo (2.245). It now goes in and comes out without resistance and with the bolt engaged in the lugs, no more land marks on my projectiles. I now feel I can shoot this without excessive pressure/safety issues.

The BIG question --- from where I stand on this topic: Why didn't Satern provide, what now appears to be a proper-throated chamber, in the first place?

[mccuistion]

Or why they said it was SAAMI spec and kind of pass the buck once confronted with our issues? If a reputable gunsmith confirmed a short throat within minutes of looking at one, that makes me wonder if Saturn might not have thoroughly checked? Just seems odd to me when several of us expressed concerns then after the fact a completely different company confirmed the suspicions with ease.

I will be sending my barrel to PF and hopefully mark can look at my bolt with it since the lugs look pretty beat up (after 25 rounds of factory Hornady ammo and 10 low velocity handloads)

To be honest this experience has kind of ruined the Grendel for me. This was my first rifle in the caliber and i'm really considering washing my hands of it and going with a .308 AR now.

[Tedward]

Or why they said it was SAAMI spec and kind of pass the buck once confronted with our issues? If a reputable gunsmith confirmed a short throat within minutes of looking at one, that makes me wonder if Saturn might not have thoroughly checked? Just seems odd to me when several of us expressed concerns then after the fact a completely different company confirmed the suspicions with ease.

I will be sending my barrel to PF and hopefully mark can look at my bolt with it since the lugs look pretty beat up (after 25 rounds of factory Hornady ammo and 10 low velocity handloads)

To be honest this experience has kind of ruined the Grendel for me. This was my first rifle in the caliber and i'm really considering washing my hands of it and going with a .308 AR now.

Don't let it ruin the caliber by one manufacture. i have a Lilja I haven't even had time to use yet and can't wait to get it going this spring. You can buy from many sources. This is one mass produced low cost barrel ($300 @ Midway or less thru the group buy). Yes it gets you in the door to shoot it and apparently one manufacture had an issue with a few barrels (Number is unknown). I have had many run thru my hands with no issue.

I just wish we (Forum Members and Satern) knew when the issue occurred so the ones with the short throat barrels could be determine and when the correction was made. Since this is a mass produced barrel, they are probably not checked after each barrel. It might have 20 that had the issue or 50, I don't think anyone knows. At some point they change the reamer or sharpen it due to what ever QC they take. At that point a bunch are probably out the door or in the next process before the change is made.

Like a hand lapped barrel, it is bore scoped and checked over by the barrel manufacture during the process a few times and you pay for that. I do not know if that is done to every Liberty barrel or a random check on every 20 or 50 barrels in the line. I just don't know there processes.

It's like not buying a Toyota because they had a gas pedal that stuck from a floor mat. That doesn't mean dont ever buy another Toyota.....Sh** Happens.

So, spend some jack, get a barrel from Lilja or Mark at PF, break out the checkbook and you will be a happy shooter. The cartridge is great!

[Walter]

There are posts that show that Liberty barrels have been short for a long time. I would bet thare there are thousands of barrels that are short. That is why Satern will not admit the problem. They do not want to pay for a recall. Once they looked at the barrels they had to know. They will not chamber factory ammo.

I have seen Brownells has Grendel barrels, and it is said they are not short. It has also been said they are Liberty barrels. So we have a case where some some Liberty barrels are short and some that are not. Which one is cut to the SAMMI spec? Brownells will not disclose who made there barrel. I bet Satern told them not to tell because this would force a recall. I think that is why Satern is scRAPEing the chamber in to a Grendel 2.

I did not want all the drama, all I wanted was a true Grendel spec chamber. That is why Mark is fixing mine.

[LRRPF52]

Or why they said it was SAAMI spec and kind of pass the buck once confronted with our issues? If a reputable gunsmith confirmed a short throat within minutes of looking at one, that makes me wonder if Saturn might not have thoroughly checked? Just seems odd to me when several of us expressed concerns then after the fact a completely different company confirmed the suspicions with ease.

I will be sending my barrel to PF and hopefully mark can look at my bolt with it since the lugs look pretty beat up (after 25 rounds of factory Hornady ammo and 10 low velocity handloads)

To be honest this experience has kind of ruined the Grendel for me. This was my first rifle in the caliber and i'm really considering washing my hands of it and going with a .308 AR now.

I wouldn't let an anomaly in the market color your entire view of the cartridge, especially when you look at recoil and performance compared to the .308 Win., which I got totally out of. There are people in the industry who have been trying to kill the Grendel from the start, and it would make them extremely happy for you to wash your hands of it.

This is one of the things that has bothered me on the rare occasion that someone gets a lemon, has problems, and just walks away, then shares that experience with others, when so many of us have been enjoying the downrange benefits of this great cartridge for years and years without issue.

Hang in there and we will help you get this sorted out. I personally don't have a warm and fuzzy about customers being left with an additional financial burden of having to send their barrel in to be reamed correctly in order to shoot SAAMI factory ammunition.

[woohoo]

.

Applying this to a 1 mil diameter change results in a .057" change in where the ogive would touch the freebore for each change of nominal diameter of .001 inch.

Agreed, I forgot to divide the final numbers. .023" at minimum, .080" at .001 larger and .137" at max chamber size. So depending on what size chamber the customer gets his COAL to touch the lands could vary .114"
I'll correct the orig post to reflect those numbers.

[JASmith]

Concur!!

... and my thanks! You have helped me understand the throat details much better than if we had not had the conversation!