All my fired brass will not F/L resize

[VEC2]

Grendel brass base measurement pics

Grendel Base Meas 2.jpgGrendel Base Meas 3.jpgGrendel Base Meas 1.jpg

Please see attached pics on base measurement position.
Have used 2 types of dies, both were Redding. See original post.
This my third AR platform I have built / reloaded for. Two 5.56mm and this 6.5 Grendel. I am not a pro but have been reloading for 40 years. Other than surplus military brass (M1 carbine) I have not had this issue w/ resizing. An oversize chamber does not seem plausible (even though the data supports it) because the upper is an AA factory piece. Gas timing fits slightly but the brass looks so nice and the gun operates very smoothly. At this time I think the brass is telling me I have a large chamber.

[JASmith]

Thanks for posting the images!

it appears that you are indeed getting bulging above the base of the case.

It is very difficult to get a good measurement of the base diameter with the wide portion of the blade because the solid portion of the base extends only a little above the extractor groove. Try using the knife edge as close to the groove as possible instead.

Your pictures from 7:11 PM are telling! There is definite bulging that I am very sure the experts will tell us is a sure sign that the bolt is opening too soon.

Even if the early opening is the culprit, running some factory ammo through the riflie and doing the same inspection will help rule put a brass problem.

[SG4247]

The base mean diameter of .453" is a little concerning.

As JAS mentioned, where from the base are you measuring that diameter?

I will check some fired brass in the morning.

I just measured 30 once fired brass the same way you did in the photos. Average diameter was .440"

[VEC2]

Thanks for posting the images!

it appears that you are indeed getting bulging above the base of the case. - VEC2-What are you looking at to make that statement? Where the brass changes texture / shine a bit up from the base?

It is very difficult to get a good measurement of the base diameter with the wide portion of the blade because the solid portion of the base extends only a little above the extractor groove. Try using the knife edge as close to the groove as possible instead. - VEC2- I thought I was to find the maximum base diameter. That would be where the pressure can expand the case, so I just move the calipers to the biggest diameter.Not using the knife blade makes it easy to find the max point. As shown in my caliper pics. Am I missing something?

Your pictures from 7:11 PM are telling! There is definite bulging that I am very sure the experts will tell us is a sure sign that the bolt is opening too soon.

Even if the early opening is the culprit, running some factory ammo through the riflie and doing the same inspection will help rule put a brass problem.

- VEC2- I don't have factory ammo, doubt there is any around here. I do have many components on hand. Could I maybe load up some lower pressure rounds? 123g AMax, 129g SST, 123g SMK, 85g Sierra,
A2520, BL-C(2), W748, H4895, Varget, TAC, CCI-450, CCI-41, CCI-400, WSR, AA brass new. Any suggestions? Thanx

Also - when I go to the range - is there some specific testing / observations I should try to do? Where the brass is ejected, does the bolt stay open on an empty mag ...........

[rwh]

If your fired brass still fits in the chamber, or almost fits in the chamber, then your chamber is over sized.

[NugginFutz]

I tend to agree with some of the others, in that it appears to be an over gassing issue. Without an adjustable gas block or gas key, there is little you can do in the way of testing. Overgassed AR's seem to eject close to the 2 o'clock and with high cyclic rates. If you want, it is possible with an unpinned gas block to eliminate the gas system entirely by loosening the gas block and turning it until the gas ports no longer align, thus turning your AR into a Single Shot rifle. A fired round can then be ejected and cases compared. IF the bulge is still present (unlikely, but possible) you have eliminated the gas system from the equation.

In the more likely event that the problem is actually with the gas system, I would follow some of the advice in pursuing an adjustable gas solution before entertaining springs and buffers as a remedy. Changing buffers and springs addresses the symptoms, whereas taming the gas system treats the cause.

[VEC2]

If your fired brass still fits in the chamber, or almost fits in the chamber, then your chamber is over sized.

Fired brass does rechamber. If I let the spring insert the round the bolt is almost in battery but it is difficult to extract. Two fingers doesn't do it.

[rwh]

Your brass is .453 at the base and the SAAMI grendel drawing shows the minimum chamber going from .4426 at the base to .4310 at the shoulder. That's a pretty big difference. Fired brass ought to fit in the chamber. If you have to muscle the bolt open than you probably do have too much gas, but it may not explain your problem. A chamber cast using cerrosafe will tell you the exact dimensions or your chamber. A light load of something like 8208, RL-15 or N133 with a 100-108 gr bullet shouldn't put a strain on your gas system. Turning the gas block so the rifle won't cycle is a sure way to eliminate the gas variable.

[LRRPF52]

What recoil spring are you using?

Measure it and report the length.

This could be a combination of the 24" barrel with RLGS, with a tight-bored Warped break creating more dwell time, and possibly a carbine recoil spring not providing enough spring force to resist the cyclic rate.

Also, try using spray-on lube that is much thinner. Imperial wax caused a bit of overworking of the brass for me too when I used it initally.

I have since gone to Hornady One Shot spray on lube, which is so much easier and I no longer see overworking the brass.

[VEC2]

Recoil Spring Data - its a stock rifle spring -

From my OP-
Gun - AA 24" Overwatch upper from AA (2008), Warped flash suppressor from AA
- lower - AA single stage tactical trigger, buffer - A1/A2, 5.9", 5.18oz (146.8g)
w/ 5 ea 18.4g weights and 1 spacer 9.4g. Spring is 12.5' free, 44 coils of .072"
round wire.

I am looking at my gas block to see how its attached. Maybe i can rotate it 90 degrees. Should i reload some "light" rounds before rotating the gas block (disabling the gas system)? I have the 6.5 Grendel Reloading Handbooks, Vol 1 and 2.
How about 100g Nosler ballistic tip, 29.0g IMR 8208XBR, Fed 205M, coal 2.200 (I'll verify that 2.200 is good w/ my chamber), 2542 f/s? Although thats not far from my 95g load in my OP.

I'll get some 1 shot but i don't think so.

I really don't want to trash 350 once fired cases.

Thanx for the help

[Younger]

Before using One Shot case lube, it is very important to clean your resizing die of ALL the old lube. Disassemble the die and clean it thoroughly. Then lightly lube the inside of the FL die with the One Shot and let dry. Lube cases as per instructions. Hope you find the problem.

[NugginFutz]

I am looking at my gas block to see how its attached. Maybe i can rotate it 90 degrees. Should i reload some "light" rounds before rotating the gas block (disabling the gas system)? I have the 6.5 Grendel Reloading Handbooks, Vol 1 and 2.
How about 100g Nosler ballistic tip, 29.0g IMR 8208XBR, Fed 205M, coal 2.200 (I'll verify that 2.200 is good w/ my chamber), 2542 f/s? Although thats not far from my 95g load in my OP.

Thanx for the help

No need to turn it quite that far. 10 deg at most. Mind the gas tube, as well.

Shooting the same ammo as before will preserve the integrity of your test, as well. Only change the one variable, or you won't know what factored into the results.

[VEC2]

Used some H one shot per instructions, thanx Younger. It did allow me to resize a few cases. Still way too much brass movement on the case. I will call Redding tomorrow to see if they have any ideas on resizing blown up brass. Got introduced to the small primer holes in the AA brass. I think I need a resizing die to reduce the diameter of the fired brass enough to be able to use the normal sizer. I've never even heard of that. I'll see. I appreciate the input guys.

NugginFutz - critical info on change 1 variable at a time. Excellent point.

[Bwild97]

Fired brass does rechamber. If I let the spring insert the round the bolt is almost in battery but it is difficult to extract. Two fingers doesn't do it.

This is not rechambering! If your bolt is not fully in battery, and you can not easily slide the carrier and fired case in and out of battery, you are definitely having an early unlock event causing the bulged cases!

[LR1955]

Used some H one shot per instructions, thanx Younger. It did allow me to resize a few cases. Still way too much brass movement on the case. I will call Redding tomorrow to see if they have any ideas on resizing blown up brass. Got introduced to the small primer holes in the AA brass. I think I need a resizing die to reduce the diameter of the fired brass enough to be able to use the normal sizer. I've never even heard of that. I'll see. I appreciate the input guys.

NugginFutz - critical info on change 1 variable at a time. Excellent point.

VEC2:

Unlocking way too soon or the chamber is way oversize. Even Alexander Arms has made rifles with chamber problems. Remember that if (and I repeat IF) a rifle maker test fires before selling, they won't measure anything. All they do is ensure it shoots and cycles. That is it. I have never heard of one that inspects the brass, let alone measure it. So, it is more than possible that AA made an Overwatch that functioned perfectly but with something wrong with the gas system or chamber.

Now for the bad news. And this comes from experience with oversize chambers in my case. The brass is done. It has been horribly stretched and even if you can bodge something together, you will have problems such as headspace issues, chambering, extraction. Your chances of an out of battery firing and or slam fire are also increased.

So, try to do something because you got a lot of money into the brass but be very happy if you can get one more shot then throw it away.

LR 1955