Help! Reloading Problems--Way Overpressure??

[jeff1383]

Maybe I got a bad batch of lapua then. I lost about 10% of my sized brass everytime due to the case bulging near the base. Same case lube method and same dies and I've gotten 7 and still counting reloads on hornady brass with no lost cases. Seems the OP is having the same problem with his lot of brass along with case head separation. Why spend the extra $ for nothing? Even if its $4.00, that gets me 100 extra primers I can use. I'm not trying to start a debate over which brass is better, like I stated earlier you're not going to out shoot the headstamp difference on the brass. I think the OP should dump his current lot of lapua brass and try another or switch brands.

[LRRPF52]

The OP's issues are being caused by something other than brass, specifically: early unlocking, evidenced by the belts on the cases. There's only one way that can happen in the AR. If they were belted before and he tried to chamber, he would experience a partial-battery FTFeed malf.

If cases are bulging a the base during the re-sizing process, the shell holder is too short.

[donthiturhead]

I had the same exact problem years back when I first started with the Grendel. After a lengthy discussion with Bill A., problem was solved. I cut back on the case lube and installed the Tubbs weight. It's attempting to extract (unlock) too soon. The weight took care of it. I believe the adjustable block will do it also. I've not had a problem since.

[bwaites]

While I would tend to agree that the difference in performance between the two types of brass is minimal, (at least so far as accuracy) and that only the best of marksmen would be able to tell the difference in the brass in that manner, long experience with the Grendel has taught me that the Lapua brass lasts significantly longer than the Hornady.

My Hornady brass has generally survived 5-7 reloads before the primer pockets have loosened so much that they no longer hold a primer consistently.

Lapua brass is widely used by those who demand the most accurate possible rounds, (if available for the caliber) including the F Class guys who compete at the National/International level, the most anal benchresters, etc. It is the most consistent brass available. Most shooters never anneal it, don't measure it, etc. They simply load it and shoot it.


For those who have had good luck with Hornady, I'm excited for you, but my experience, after shooting enough to burn out barrels in the Grendel, is that Lapua is more consistent, and lasts longer.

I have photos of brass that looks just like that pictured earlier in this thread, and I know exactly what it takes to create them, and that is a hot load in a rifle that has a gas system which is a little to short for the load. In my case, its a rifle length system in a 28", but depending on barrel length, it could be any similar variation. After loading somewhere in the neighborhood of 12,000 Grendel loads over the last 5 years, I'm convinced it is an unlocking problem, exactly as described by LRRPF52, especially since an extra power spring and the Tubbs system fixed it in my rifle.

[bronco_buster]

IMG_0665.jpg

I don't have anything that I can feel as far as a "belt" after resizing. Sure, the case looks a little shiny...but nothing that's palpable. I have many other cases in other calibers that end up looking identical to it. See above...

Specs on rifle:

Midlength gas 18"
VLTOR Upper
RRA Chrome BCG
Satern?? Bolt
Magpul ACS Stock
Carbine Buffer/Spring
6 Position milspec tube
Non adjust YHM clamp gas block
Geissele SSA-E Trigger with Bushy LPK
YHM FF Handguard/Barrel Nut Torqued to 75ft/lb

[ricsmall]

I have not reloaded for the grendel, but I have reloaded thousands of rounds for approximately 22 different calibers and every available type action(except full auto), and I have never had brass do that in the sizing process. The only way that would happen is with a short shellholder or an out of spec die. Essentially you would be running the case in the die by AT LEAST .020 too far. If thats happening, you would definitely notice the camming of the press to be way too soon.IMO. I would have to agree with the early unlocking of the action. It takes alot of pressure to create that "belt" on a non belted case.

Bronco, that shiny area above the web is normal to an extent. I made a feeler gauge to detect case head separation in that area. you can buy them as well IIRC. It could be the picture but the junction of your case shoulder and case body look slightly radiused. Probably the picture.

[Bill Alexander]

The general rule of thumb for an AR is that the timing is created from the port position and the acceleration of the carrier group comes from the port size. Obviously these things are somewhat interrelated but it is a good starting point.

Our examination of the 18" barrel has shown that the mid gas system while a little enthusiastic can be easily mitigated by reducing the gas port size. Typically the port is 0.073" for the correct operation and the slight change in duration of pressure at the port actually helps reliability. The 16" barrel sharing a common port position is sensitive to loading and to ensure good functionality with a variety of loadings the port must be slightly oversized at 0.090" Within manufacturing the elimination of the 90 grain TNT loading and its replacement with the 100 grain Berger alleviated much of these problems and a port of 0.078" can now be applied. The same examination can be seen with the 20" barrels. Typically these will run beautifully on a rifle length port but are again sensitive in comparison to the equivalent 24" barrel which is very well suited to a rifle gas system and an 0.093" port. This leaves the 20" barrel either fussy about loads or it must be slightly heavily gassed. In the instance of the 20" barrel we prefer a little fussiness. I have not examined an 18" rifle gas system barrel but interpolation would indicate it may be very problematic unless either loaded hot or over gassed. I will reserve judgement however until such work is undertaken. The oddity in this is the 28" barrel. These will operate without fuss but must be loaded judiciously because the rifle length system has now too much dwell time and the opening can reveal residual pressure is still present in enough quantity to deform the cases. From the manufacturers standpoint I rather like how the rifle acts as a sort of built in pressure relief gauge that punishes transgressors by destroying all their brass, but it is not an elegantly set up gun. Moving the port forward 2.0" helps the set up but now promotes overloads to get reliable function.

Returning to the OP the cases shown are not indicative of a simple timing issue but there is a lot of pressure present as indicated by the case head movement into the ejector and extractor recesses. While the cause remains slightly elusive I would again caution against using the rifle until the problem is correctly diagnosed and remedied.

In instances where such cases occur we typically find a number of underlying problems. Chamber breach chamfer depth and edge blend should be within strict limits or the case becomes unsupported beyond the fillet of the internal web. Chambers may be wallowed by polishing or machine misalignment and finally the breach itself may not be long enough within the barrel extension. This would cause the expansion but does not explain the pressure excursion. Now I return the chamber neck length, the throat configuration, internal finish and lastly the internal bore dimensions although these are less particular in all but pressure breaches.

[bronco_buster]

The general rule of thumb for an AR is that the timing is created from the port position and the acceleration of the carrier group comes from the port size. Obviously these things are somewhat interrelated but it is a good starting point.

Our examination of the 18" barrel has shown that the mid gas system while a little enthusiastic can be easily mitigated by reducing the gas port size. Typically the port is 0.073" for the correct operation and the slight change in duration of pressure at the port actually helps reliability. The 16" barrel sharing a common port position is sensitive to loading and to ensure good functionality with a variety of loadings the port must be slightly oversized at 0.090" Within manufacturing the elimination of the 90 grain TNT loading and its replacement with the 100 grain Berger alleviated much of these problems and a port of 0.078" can now be applied. The same examination can be seen with the 20" barrels. Typically these will run beautifully on a rifle length port but are again sensitive in comparison to the equivalent 24" barrel which is very well suited to a rifle gas system and an 0.093" port. This leaves the 20" barrel either fussy about loads or it must be slightly heavily gassed. In the instance of the 20" barrel we prefer a little fussiness. I have not examined an 18" rifle gas system barrel but interpolation would indicate it may be very problematic unless either loaded hot or over gassed. I will reserve judgement however until such work is undertaken. The oddity in this is the 28" barrel. These will operate without fuss but must be loaded judiciously because the rifle length system has now too much dwell time and the opening can reveal residual pressure is still present in enough quantity to deform the cases. From the manufacturers standpoint I rather like how the rifle acts as a sort of built in pressure relief gauge that punishes transgressors by destroying all their brass, but it is not an elegantly set up gun. Moving the port forward 2.0" helps the set up but now promotes overloads to get reliable function.

Returning to the OP the cases shown are not indicative of a simple timing issue but there is a lot of pressure present as indicated by the case head movement into the ejector and extractor recesses. While the cause remains slightly elusive I would again caution against using the rifle until the problem is correctly diagnosed and remedied.

In instances where such cases occur we typically find a number of underlying problems. Chamber breach chamfer depth and edge blend should be within strict limits or the case becomes unsupported beyond the fillet of the internal web. Chambers may be wallowed by polishing or machine misalignment and finally the breach itself may not be long enough within the barrel extension. This would cause the expansion but does not explain the pressure excursion. Now I return the chamber neck length, the throat configuration, internal finish and lastly the internal bore dimensions although these are less particular in all but pressure breaches.

So I guess the question in my mind...what do you recommend that I do with the rifle? I have some cases that I've trimmed to 1.480 which I was planning on loading in the 26 - 27g range, seating the OAL to 2.20 and see if the problem persists. I mean, the question in my mind is why can I cycle Wolf and AA factory loads, even reloads that I made with AA, Hornady and PPU brass with W748 powder, but with all variables remaining equal (same dies, bullets, chargemaster, rifle), the 8208XBR is the only variable which was changed prior to the problem developing?

What would be the steps needed to diagnose this issue? I did unbarrel the upper, dropped a few resized rounds into it as well as some factory, and they *look* like they protrude equally, I really can only guesstimate as my calipers won't clear the barrel extension. But I mean I can't see anything outrageously different, but then again I do understand that .02 difference could be huge with respect to pressure/danger, and not easily observed with the naked eye, so I recognize that eyeballing it as it sits in the chamber would not really be overly diagnostic.

Do you recommend sending the barrel back to Satern? Would it be worthwhile to try a heavy buffer or spring? Nothing in my dimensions and measurements looks grossly abnormal or out of spec does it?

On one hand I don't want to waste anybody's time, but on the other, I'm not willing to a Kaboom at 60000psi either. So I'd really like to know what the troubleshooting steps would be in my case, since I think I'm exhausting my ability to diagnose it without firing it.

[LR1955]

So I guess the question in my mind...what do you recommend that I do with the rifle? I have some cases that I've trimmed to 1.480 which I was planning on loading in the 26 - 27g range, seating the OAL to 2.20 and see if the problem persists. I mean, the question in my mind is why can I cycle Wolf and AA factory loads, even reloads that I made with AA, Hornady and PPU brass with W748 powder, but with all variables remaining equal (same dies, bullets, chargemaster, rifle), the 8208XBR is the only variable which was changed prior to the problem developing?

What would be the steps needed to diagnose this issue? I did unbarrel the upper, dropped a few resized rounds into it as well as some factory, and they *look* like they protrude equally, I really can only guesstimate as my calipers won't clear the barrel extension. But I mean I can't see anything outrageously different, but then again I do understand that .02 difference could be huge with respect to pressure/danger, and not easily observed with the naked eye, so I recognize that eyeballing it as it sits in the chamber would not really be overly diagnostic.

Do you recommend sending the barrel back to Satern? Would it be worthwhile to try a heavy buffer or spring? Nothing in my dimensions and measurements looks grossly abnormal or out of spec does it?

On one hand I don't want to waste anybody's time, but on the other, I'm not willing to a Kaboom at 60000psi either. So I'd really like to know what the troubleshooting steps would be in my case, since I think I'm exhausting my ability to diagnose it without firing it.

BB:

Didn't Satern recommend you send the barrel and bolt back to them? And, didn't Bill Waites say that there was a run of Satern barrels that were not made well? And, didn't Alexander just talk about the potential of the chamber being out of spec?

Maybe you ought to send the barrel and bolt back to Satern as they recommended.

LR1955

[Brian]

Maybe I got a bad batch of lapua then. I lost about 10% of my sized brass everytime due to the case bulging near the base. Same case lube method and same dies and I've gotten 7 and still counting reloads on hornady brass with no lost cases. Seems the OP is having the same problem with his lot of brass along with case head separation. Why spend the extra $ for nothing? Even if its $4.00, that gets me 100 extra primers I can use. I'm not trying to start a debate over which brass is better, like I stated earlier you're not going to out shoot the headstamp difference on the brass. I think the OP should dump his current lot of lapua brass and try another or switch brands.

I had this exact same issue when using Lapua brass. My load was 30.6 AA2520 123 Amax out of a 20" barrel with rifle length gas. I thought I was overgassed or early unlocking causing these belted cases. I tried an adjustable gas block all the way to completely shutting off the gas. But I always got the same results after 1-2 reloads the lapua brass would develop a belt and would not chamber. I was at wits end but I had 20 pieces of factory Hornady ammo and it worked flawlessly and after 10 reloads the Hornady brass still works and looks just fine. Exact same load same sizing procedures same everything. Now I exclusively use Hornady brass and have never seen the problem again. Go figure

[sneaky one]

Rasper- give up the data you sent me about gassing- originally sent to you from Bill A.- as to the diff. bbl. lengths, and gas needs-results. It said , in the end,,, nobody really needs an adj. gas block. - IIRC.- Sorry about the joke in there... the end. If you are seeing a belt- of , or any thing odd,-send it back! -OMG !! This round should run thru like butter,- with minimal damage to brass, if you have good mags.. and a decent chamber....

Brian,, also sounds like a sizing issue-maybe? Which dies are you using ? Sizing lube ? You don't need much to size this case.

A heavier buffer, say an H2-will correct a few problems also. Its' a great fit for my 20" AA bbl. The AA, and Horn. brass are close to -same as exterior dimensions can be... I size and load -equally-- between them---- never had a problem at all.

[rasp65]

Sneaker I thought I told you to put that info in a safe place? Here it is:"Within the Grendel models the only unit I would regard as over gassed is the 16" Tactical. The 10.5", 18" and 20" are slightly under while the 24" and 14.5" are about perfect. We are currently correcting the 16" with the removal of the 90 gr TNT ammunition and the replacement of the 100 Berger HPBT. The general rule of thumb for an AR is that the timing is created from the port position and the acceleration of the carrier group comes from the port size. Obviously these things are somewhat interrelated but it is a good starting point." One thing you must remember though is that AA uses different buffers and carriers to balance the system. If the parts aren't balanced then the adjustable gas block is the only way to get back to balance.

[Brian]

Rasper- give up the data you sent me about gassing- originally sent to you from Bill A.- as to the diff. bbl. lengths, and gas needs-results. It said , in the end,,, nobody really needs an adj. gas block. - IIRC.- Sorry about the joke in there... the end. If you are seeing a belt- of , or any thing odd,-send it back! -OMG !! This round should run thru like butter,- with minimal damage to brass, if you have good mags.. and a decent chamber....

Brian,, also sounds like a sizing issue-maybe? Which dies are you using ? Sizing lube ? You don't need much to size this case.
A heavier buffer, say an H2-will correct a few problems also. Its' a great fit for my 20" AA bbl. The AA, and Horn. brass are close to -same as exterior dimensions can be... I size and load -equally-- between them---- never had a problem at all.

It could be a sizing issue surely. I am using Hornady dies, I have used Hornady one shot and Dillon lube. I also use exactly the same procedures with Hornady and Lapua brass as well. The belts would show up on the Lapua brass after the second or third reloading. The Hornady brass well I have a lot of 20 pieces that are over 10 reloadings with no issues.

[sneaky one]

Brian, Did you follow the manufact. setup.? = die-shellholder= just a contact-w/ ram all the way up, as a start point,, etc.? Kinda sounds like you are pushing the upper 2/3rds of the body back. It weakens the web area- shows up as a flaw a few shots later. This has been noticed before. If you are pushing extra hard at the end of the stroke (no jokes)=you are oversizing the Grr. case. Run a search on this forum. Hopefully you don't have a short chamber. It seems unlikely the lap. brass is bad. Start from scratch.

[Brian]

I don't have any Lapua brass any more. The Hornady brass I use now goes through the sizing die like butter bumping the shoulders .003 And I haven't lost a single piece of Hornady brass yet through several cycles with a fairly stout load of 30.6 AA2520 with 123 Amax's Not saying there is anything wrong with the Lapua brass it just doesn't seem to play nice with my chamber and my loads and dies.