.2925 Fired Case Neck Measurement

[grin&dull]

I’ll try not to reinvent the wheel here but I have a question about chamber pressure and ammunition. I have a .264 BHW barrel and it seems adverse to the 120 gr MPT Wolf ammo, doesn’t want to eject, bulges in the web case wall junction, and the primers are flattened. While the 123 A-Max Hornady ammo runs fine.
Anyway something I finally got around to doing was mic the case neck on some fired brass it measures .2925 / .293 could the what seems like a tight neck even with reading at some point the chambering was with a .291 diameter be a contributing factor to the pressure issue and would opening up to the .300 size possibly help or even be feasible?
I’m assuming my barrel is at .295 but I haven’t tried to get a gage pin in it at this point.
Or is this just poor quality brass from Wolf?
Thanks for any and all input.

[LRRPF52]

The Grendel chamber has a compound throat angle to deal with a wide variety of bullet shapes and seating depths. If the ogive of the PPU MPT is jammed into a .264 LBC chamber ( a chamber that PPU didn't have when doing the load development for their ammunition), then that could lead to over-pressure. There also was an earlier lot of 120gr MPT that seemed to be pretty hot in people's Grendels, so there are more possible factors in this case.

Easy answer is stick to Hornady, but not the most affordable one either.

[Bennybone]

I have noticed the brass of the Wolf MPT is very soft, I have dented the shoulder of many rounds by simple hand cycling of rounds, I read yesterday that the brass is so soft that upon reloading the neck area has issues supporting the projectile without crimping, someone guess that the brass would be good for 1 maybe 2 reloading cycles.

I wonder if Hornady and Lapua brass, after 4 -5 reloads, will start to "stick" in 264 chambers once that brass becomes less rigid.

BB

[LR1955]

I have noticed the brass of the Wolf MPT is very soft, I have dented the shoulder of many rounds by simple hand cycling of rounds, I read yesterday that the brass is so soft that upon reloading the neck area has issues supporting the projectile without crimping, someone guess that the brass would be good for 1 maybe 2 reloading cycles.

I wonder if Hornady and Lapua brass, after 4 -5 reloads, will start to "stick" in 264 chambers once that brass becomes less rigid.

BB

BB:

This is the first I have heard this about the current lots of Wolf MPT. If you are using the first lots that came out about five years ago, maybe.

The reason why the necks aren't holding the bullet is because the Wolf brass is thinner and a standard Grendel sizing die won't size the necks down enough. Thats why most of us recommend using the Redding sizing die that has colletts for different sizes of necks. I imagine the Lee sizing die would size them down too as it has a very small neck diameter that will destroy Lapua brass by overworking the necks.

I get eight or so reloads from the Wolf stuff before the primer pockets open up too much. Never had a cracked neck with the Redding dies.

LR1955

[Bennybone]

Guys -

I tried 40 rounds of Wolf and all stayed in the chamber, a few days ago I got ahold of some Hornady 123gr Amax factory ammo and experienced the same stuck case issue.

The barrel is an ARP 264 lbc with a .297 neck , a guy with a caliper took a measurement for me of the fired case (neck) and it was .300 .

Original poster - Have you tried a different extractor spring? A stronger one to be more specific?

This was suggested to me as a possible fix based on the thought that upon combustion the bolt extractor was slipping of the rim of the case.

I have another extractor spring in the mail on its way to me and will report back the results.

Let me know what you figure out with the Wolf ammo in your 264lbc

BB

[grin&dull]

Just to clarify with my rifle the Wolf ammo wasn’t sticking in the chamber it sometimes fully cycled and ejected (roughly 30% of the time) the other failed to eject with the bolt locked back on the last round with the case laying in the gun loose or smoke stacked. The spent brass has a bulge at the web of the case and the primers are flattened. Seemed to shoot a pretty good group.
The Hornady cycles and ejects flawlessly, both the rifle and ammo function as designed and shoots a good group. Spent brass shows no signs of pressure.
As noted in the title they measure at .2925 at the neck after shot.
If I ever figure out again how to post a picture on this site I’ve finally got a good photo of the two cases side by side. Got it Hornady on left Wolf on the right.

[sneaky one]

Wow Ben, my chamber is .300, and the O.D. of the fired AA brass is .291-.295.... I went through this hell in 08' w/ wolf SP ammo-why was it ever made-sold-- the Dfender extractor upgrade has worked w/ all brass for the last 1 k of shots through the rifle, I recently added an H2 buffer, it seemed to help smooth the gun out a bit- Do you have the std. buffer wt. in the gun? I wish Les baer never got involved in the 6.5 Grr arena- he builds a fine .45-1911 handgun, and some awesome AR's in 5.56-but his whack idea for this chamber is pissing off many people, unfortunately you- and grin are part of the angst against this chamber design. Bill A said a while back--he regretted ever designing a Grr chamber -neck- smaller than .300. I noticed the few that claimed to have an old .295 neck chamber---they never post anymore. Hmmmm.. what does that imply? A Sammi certified Grendel chamber is the way to go, to use this ammo, data. The data that pops up here can be used -( backloaded a grn. or -so) then worked back up with a level of Confidence, the idea is we all have the same chamber., as close as possible. I think it would also help with a few QC issues that unfortunately will show up once in a while- for say-AA.-, Manufacturing anything is a huge effort, and then to Assemble what you purchased from a manufacturer, or 20 -it's a crap shoot some weeks. ( Maybe try an outside neck turn on 1-just for trials sake-??? Squeaky clean the chamber, and the brass . )? If that's to no avail-get it rechambered or get a refund. We look forward to your pig hunt vids w/ 6.5 Grr knockin em down. Good luck.

[Drifter]

The barrel is an ARP 264 lbc with a .297 neck , a guy with a caliper took a measurement for me of the fired case (neck) and it was .300 .

That doesn't seem to jive if we're talking fired brass. The brass will expand to chamber size, then retract 1 or 2 thousandths. Not sure how a fired brass case neck can measure larger than the chamber's neck diameter. A .297 chamber neck should result in a fired brass case neck of ~.295 or so.

The OP mentions a fired brass neck size of ~.293, so he probably has a chamber neck diameter of .295, which is typical for 264 LBC chambers.

finally got a good photo of the two cases side by side. Got it Hornady on left Wolf on the right.

In addition to the bulge you mention, it appears that there might be a difference in the cartridge rims (shape and thickness), which might contribute to unreliable extraction and ejection. Perhaps the extractor isn't getting a good grip on the Wolf rim, but works fine with Hornady brass.

[grin&dull]

Some valid points being made about standardization of chambers and ammo but if everything worked every time we'd all just be bored and measuring group sizes. With some things not working 1st time out we've got something to talk about.
While it would be great if this rifle worked with the cheaper ammo it's not the end of the world that it wants to run a better made bullet. Who knows when Wolf gets around to putting the 110 gr steel case stuff out this rifle may take a liking to it.
As I've said this was not built by me to be a high volume of fire gun, I've got others that are cheaper to operate, this one is my version of a hunting rifle for my son. With the Hornady and more than likely some other good quality ammo the rifle runs and shoots fine so I'm good for now.
So it comes down to I'm happy with my one and only AR build and we'll see if the boy gets out and goes hunting with his buddies. The boy (31 yrs old) doesn't know it yet but he's getting some stuff to let him do his own build for Christmas, we'll see how his 1st build goes and what choices he makes on calibers and components.
Benny hope you get it ironed out without having to throw a bucket of money at it.

[Bill Alexander]

Your chamber neck is too tight and is probably too short to the transition angle. Your extractor has a sharp section somewhere on the edge.

[grin&dull]

When some people post a reply or comment I take it with a grain of salt, but when you get information from a known expert I take it without any seasoning. Thanks for the information to all and especially Mr. Alexander.

For the moment I’m a little strapped for cash to put into gun related things but when I have a couple of dollars freed up I’ll look at addressing the chamber on this rifle some more. In the mean time I’ll get a look at the extractor and see if I can see anything on it.

Have to wait to see if something can be done on the chamber without sinking my budget and my wife’s understanding of my hobbies.

[bwaites]

The extractor fix is easy, a little GENTLE work with a Dremel and fine sanding or cutting disk. I used the floppy superfine disk and it worked wonders.

The throat may actually get better as you use, simply due to break in, though some guys have resorted to a touch up with a throating reamer.

[Bill Alexander]

I am still worried about how tight that neck is. If brass is dropping out at 0.2925" and I assume it is being measured with a good micrometer then that will be the neck size. Brass for the Grendel seems to near exactly mimic the chamber neck size when fired brass is measured. Strangely the shoulder moves further than the chamber by a fraction and the body diameters are size on size or a few tenths below

[Bwild97]

I used Stokesrj's method with the JB and it worked wonders for the throat in my chamber. I gained a few thousandths of OAL with several projectiles!

[grin&dull]

I'll take some brass into work tomorrow and triple check my measurements but I'm pretty sure I got the numbers right. At this point I just want to make sure I don't throw the baby out with the bath water in a fix to the issue. While your Alexander Arms barrels are the gold standard for this caliber I went with a BHW barrel for the rifling type as a long time Glock shooter and knowing if I can get my son to run a bore snake through it that's about all the attention it will get. I have some concerns in the back of my mind about the chamber on the rifle and it's refusal to run the Wolf ammo but seeing how it will run with a good quality ammo with no problems at this time I'm not going to go into a tail spin. When time and money are on hand I'll see if I can't get this upper off to someone (possibly AA if ya'll work on other peoples barrels) who is able to make any adjustments to the chamber needed to enhance the reliability with a wider range of ammo including reloads. Again thanks.

Verified the neck size they tend to run right at .293.