6.5 Grendel PTG Reamer

[Tedward]

After measuring all of mt Liberty barrels with the provided bolts, they all passed the Go and No-Go Manson Gauge tests. Bolt and chambers all locked and the bolts turned with the Go gauge and it did not lock with the No-Go gauge, basically meaning the chamber is ok with the bolt headspace.

Now I wanted to test the throat. I was looking for a gauge to measure the Grendel Throat but couldn't find one for that caliber and I saw companies make them for the popular 223, .762 and 30-06. During the Google search, I looked thru PTG and there reamers (link attached) . https://shop.pacifictoolandgauge.com...7tgtvljb0lf176

Looking at the image of the reamer (enlarge image), you can see there is not any freebore and the decreased size right after the dimension of the case cut. This is where I'm seeing the issue presented of bullets making contact in the throat.

If the PTG reamer is correct, which I assume it is, no wonder the bullets are touching the throat. I just wanted to pass along the image of the reamer so you might understand the design.

News to me and wanted to share the link.

[rebelsoul]

I have three grendels from Model 1 kits. My 20" works fine but the 16"(both) will yank the bullet out of the case(Hornady 123 amax & sst) when I hand crank it after a few rounds fired. After I clean them they work fine. Less than 100 rounds fired in those barrels(cheap ammo shortage). Are you chasing a similar problem or should I bark up another tree.

[cory]

I have three grendels from Model 1 kits. My 20" works fine but the 16"(both) will yank the bullet out of the case(Hornady 123 amax & sst) when I hand crank it after a few rounds fired. After I clean them they work fine. Less than 100 rounds fired in those barrels(cheap ammo shortage). Are you chasing a similar problem or should I bark up another tree.

Your barrels shouldn't pull the bullet out of the case, ever. Does your fired brass show any signs of pressure?

[rebelsoul]

I'm not smart enuff to tell. What do I look for.

[cory]

We're both in madison. If your free one weekend bring your rifles by and I'll measure the chamber for you. I'm assuming it was SST rounds that you were pulling out of the case.

[LRRPF52]

If there is +/- .001" on the reamer, the -.001" will screw it up, and cause the issues we are seeing.

Tedward, the link you posted is not for the SAAMI 6.5 Grendel, it's for a "6 Grendel".

The SAAMI Grendel chamber is very forgiving for ogive shape and seating depth, even to the point of being labeled a sloppy chamber by many critics. If the reamers are cut with an allowable -.001", that will create tight chambers with a pronounced short throat, exactly as some are seeing on their barrels.

Just in the neck alone, there is .010" - .015" room, since the chamber length to the neck mouth is 1.530", while most brass is 1.515"-1.520". Factory ammo should not be jamming into the lands, but if a .001" tighter reamer was used, this is a very real possibility.

[customcutter]

After measuring all of mt Liberty barrels with the provided bolts, they all passed the Go and No-Go Manson Gauge tests. Bolt and chambers all locked and the bolts turned with the Go gauge and it did not lock with the No-Go gauge, basically meaning the chamber is ok with the bolt headspace.

Now I wanted to test the throat. I was looking for a gauge to measure the Grendel Throat but couldn't find one for that caliber and I saw companies make them for the popular 223, .762 and 30-06. During the Google search, I looked thru PTG and there reamers (link attached) . https://shop.pacifictoolandgauge.com...7tgtvljb0lf176

Looking at the image of the reamer (enlarge image), you can see there is not any freebore and the decreased size right after the dimension of the case cut. This is where I'm seeing the issue presented of bullets making contact in the throat.

If the PTG reamer is correct, which I assume it is, no wonder the bullets are touching the throat. I just wanted to pass along the image of the reamer so you might understand the design.

News to me and wanted to share the link.

I looked at the picture in the link. I also looked at the picture of the reamers for some of the other calibers (5-6), and they look like the same photo. I'm not sure that is the picture of an actual 6.5 grendel reamer. All of them had "4/13" printed on the reamers. Don't know if it means anything or not.

[Shivesy]

After the problems that I had with my McGowen (PTG Reamed) barrel and some of the issues that I have read about these Saturn barrels. I think in the future I would request my barrel maker use a different reamer. Not to say all PTG reamers are bad or even the PTG Grendel reamer are bad, but I personally wouldn't feel right about taking a chance on another PTG reamed Grendel barrel.
After discussing my McGowen problem with members of this site a few months ago, Bill Alexander stated that Manson Precision Reamers make fine Grendel reamers and he recommended using them. I believe in the future that I would request or at least ask my barrel maker if he would, or does he use these Manson Reamers.
I am wrong for thinking like I do?

[NugginFutz]

I can't see how any measure of caution in the shadow of the last few week's debacle would be considered wrong.

My experience with PTG gauges and tools have always been positive. That doesn't necessarily mean that the entire product line is without issues. If Bill A. says he has a preferred reamer maker, then I don't see how wanting to use the same can go wrong.

The only catch to that way of thinking is that it may well limit your choices of custom barrel makers. Either way, the onus is on you to decide if a manufacturer has enough credibility to believe them when they say "Sure... we use, uhm, what was the name of that reamer you mentioned?"

[BjornF16]

Tedward, the link you posted is not for the SAAMI 6.5 Grendel, it's for a "6 Grendel".

^^^^ This

Trying to deduce anything from a picture (disregard it not being a Grendel reamer) is ridiculous.

But I think you may be onto something...PTG reamers may not be in SAAMI spec (actually, I already posed that question in the locked thread).

[rebelsoul]

Thanks Cory, just like highschool I get to cheat off someone else's home work.

[Shivesy]

This is a quote from Bill Alexander concerning my issues at the time...

"The SAAMI spec reamer has plenty of clearance, it was designed to be extremely tolerant of bullet design, to the extent that many accuse it of being a machine gun chamber. The tolerance for the reamer is not specified within SAAMI only the minimum chamber size. The tolerance is the toolmakers descision.

The chamber is set to allow the guns to run excessively dirty and the carbon fouling deposits have clearance.

Hornady ammunition and the 123 Amax was designed for the Grendel chamber. Hornady is the SAAMI sponsor for the Grendel.

You have just found that you do not have a (correct) Grendel SAAMI chamber."

I take that quote as meaning the tooling could be out of spec, or that McGowen didn't use the tool correctly.

[cory]

Thanks Cory, just like highschool I get to cheat off someone else's home work.

Well in that case this going to be a little weird. I don't know what it's like to be the kid that did the homework in highscool. haha

[NugginFutz]

^^^^ This

Trying to deduce anything from a picture (disregard it not being a Grendel reamer) is ridiculous.

But I think you may be onto something...PTG reamers may not be in SAAMI spec (actually, I already posed that question in the locked thread).

As I see it, the issue here is that some of us have been asking the manufacturer to affirm that their product is in spec. According to the second-hand responses we've been reading in the closed thread, XCR, through rickOshay, (post #112) tells us Steve Satern said "We buy the reamers from PTG and JGS, and they have the print from SAAMI and that's what we follow." and that "As far as the throat goes, we will talk to PTG and JGS to see if there has been a change that we have not been made aware of. ". His follow up to that is related by Tedward, (post #306), when he wrote "(Steve) has taken this concern to PPG (sic), the reamer manufacture (sic), and both of them have aggreed (sic) it is the way the throat was designed by AA and submitted to SAAMI along with Hornady." Bwaites confirmed this in post #497, when he wrote that Steve Satern "...still feels that the chambers are dimensionally correct.".

So, you see, according to the three parties in question (Satern, PTG and JGS), the issue is settled, as far as they are concerned. In other words, it is apparently up to the consumer to prove that the reamer (and resulting chamber) is not in spec, since PTG, JGS and Satern have reportedly taken the position that they are. The key to this would obviously be that when a qualified third party evaluates the reamer, they compare it to the published standard.

Even then, it will be up to Satern or PTG to agree that the findings of that third party are valid, or that the reamer examined is dimensionally the same as the one they are using. Throughout the previous thread, though, nowhere did we hear directly from Steve Satern. Until then, in my opinion, his official position on these reamers (and barrels) is still officially unsettled.

We have been assured, however, that Satern will be making a post on this site, within the next day or so (bwaites, post #497). What it will reveal remains to be seen.

[cory]

As I've said before, it's not that there was a mistake made, it's how it was responded to. I'm concerned with how this has been responded to. However, most of the information has come second hand so I'm going to reserve my final opinion a bit longer.

If it's true that the barrels are in "spec" and it'll need to be sent back on the buyers dime to be altered(fixed), then I would be very uncomfortable about buying a barrel from them in the future. However, if they were to do the right thing and take responsibility, then they'd have a future customer for certain.

Following these Liberty barrels since XCR came on the scene, advertising significantly higher than normal MVs, I suspect that these liberty barrels may be a deviation of the Grendel Chamber. I have no problem with that, but they should be marked accordingly.