308 Primers Textured after Firing

[LKaler]

Hi,

This is my first post on these forums, and from what I have read so far everyone here is very knowledgeable. I recently started reloading for my Remington 700, .308 Win with a 20" 1:10 twist. I purchased some Winchester virgin brass, and full length sized and loaded it with 45gr Varget and a 150gr SPBT Hornady Interlock Bullet. I fired all 50, with no signs of overpressure. It was chronoing a average of 2525fps. After firing those, I neck sized and loaded with 46gr of Varget and used the same bullets. Those averaged 2705, and it was a very hot day, 90 degrees. According to my Lyman Manual, the max load is 47gr of Varget for the specific bullet I am using. I am also following their OAL recommendations. I do not know how much a difference my shorter barrel effects the velocity, so I can not use the 2891 FPS as a apples to apples comparison to what I data I have.

I checked the primers after firing 10 test shots, and noticed that they are textured which has to be from the bolt face. The primers do appear to have a small amount of flattening occurring, but they still retained their beveled edges around the entire outside of the primer. I know I set the primers deep enough, so I have to assume the primer is being pushed back when it is fired, enough to impart a texture but not enough to flatten it. I guess my questions are:

Does anyone have any chrono data on a 20" Barrel and 150gr SPBT?

Has anyone seen primers get textured like I am experiencing?

Judging from the pics, is that a acceptable amount of primer flattening?

Should I pull the remaining 40 i have loaded, and lower the load to sub 45gr? Should I toss the brass that have already been fired?

Sorry, this is a long post. Any input would be greatly appreciated.

Edited June 21, 2012 by LKaler

[LKaler]

Sorry, it will not let me post pics, as I am a new member. I will work on getting one up asap

[LKaler]

Hopefully This will work in until i can post URLs,

Also, The pic looks like there us cratering, but its just glare. The area around primer strike is smooth

Edited June 21, 2012 by LKaler

[Cotys]

The Varget weight seems a little light. Would that be 45 grains? .308 Varget loads seem to fall around 45 to 47 grains.

I ran Varget 45 grains, 150 Hornday and a 20" barrel in QuickLoad; it estimates a muzzle velocity of 2698 fps; 47 gr = 2819 fps.

One person is showing an actual of 2703 with a 22" barrel and 45 grs of Varget.

Edited June 21, 2012 by Cotys

[LKaler]

I am sorry, i have been loading thousands of 223's with 26grs recently. You are correct, 45 and 46grs.

[Cotys]

I just checked the Hornady manual, they show 44.9 grains at 2700 fps as a max for Varget with their 150 grainers. I see a lot of loads hotter than that, just FYI.

[LKaler]

Yeah, Lyman has a much higher max load and max fps. Its a pretty large difference. What do you think about the photo I posted? Also, does Hornady have the same load data for their SPBT and SP with a flat base interlock 150gr pills? i know It usually is the same starting, but sometimes different max for BT vs FB. Lyman only has data for a standard 150gr SP. I have a few hundred of both style bullets.

[Cotys]

Hornady shows the same load for all their 150 grainers, 7 different bullets.

I reran the 46 grain load at 70 degrees(58758 psi)and 90 degrees(60749 psi), with 62000 psi max SAAMI. QuickLoad shows all those loads below max pressure (all estimates of course).

The picture came through, you can see the texturing and it looks flattened. What is your OAL? I'll check it against QuickLoad defaults, it can make a big difference.

Was the ammo laying out in the sun before being shot? I've read in one test, where ammo laying in direct sunlight increased internal pressures by 4,000 psi. That could put you over the 62000 psi.....

[LKaler]

Off the top of my head i think I ran 2.730 with lyman listing max as 2.735. They were exposed to some heat, as they were sitting in my trunk for about a hour.

I really have no experience with flattened primers, I usually load all my other calibers on the conservative side. If the pressure is enough to flatten the primer, has it permanently damaged the primer pocket? or should I be more concerned with the base of the case and internal thinning?

[Cotys]

We'll see what people say about the look of the primers. Makes me want to go look at some of mine tonight, if I have any not processed yet.

All your data looks good. The actual chrony reading of 2705 says you are in the good range. I even upped the temp to 110 degrees, no problem there with pressures.

From looking at the picture, I would say the brass would be fine.

Edited June 21, 2012 by Cotys

[LKaler]

I am not one to blindly follow the reloading manual, but being under the max charge, and under the the max velocity I feel pretty comfortable. The pics make the primers appear a little more flat then in person. there is a nice rounded gap between the primer and pocket around the edges. But am i correct in assuming the primer is backing out and touching the bolt face? I know they were seated with enough depth. Thanks for all the help Cotys, your helping me make my day at the office really unproductive, haha.

[Cotys]

Glad to help corrupt a fellow reloader.

I had wondered if the pictures exaggerated flattening a little. Other signs would be cratered primer with a raised rim (don't see it) and carbon around the primer (don't see it). A little flattening is normal. Chrony shows to be right where you would expect. All in all I think it may be interesting with the texturing, but not a problem.

[Cotys]

Oh, another sign of over pressure is a bar / scratch on the base of the brass where the extractor sits (don't see it either).

[LKaler]

Another thing that is of concern in the base of the cartridge has a very small bulge. It is about 1/4" from the base. From the neck down to the bulge the case has a "worn" appearance, and from the bulge to the bottom of case it is still very polished. The used case is still chambers and extracts with ease. Is the case just being formed to my chamber, or do i need to worry about case head separation? Once again, this is my first bolt action and 308, so please bear with me. Thanks

Edited June 21, 2012 by LKaler

[LKaler]

Cotys, started a new thread for that last post. Figured I would separate the issues.

[Cotys]

Sounds like it is being fire-formed to your rifle, especially if the empty chambers fine. A lot of people just neck size them once it is fire-formed to their rifle. I still do full length resize on them all.

I have a bolt gun and an HK-91. The HK-91 is really a terror on brass. The chamber is fluted and the brass comes out with the flute indented the length of the brass and sometimes a burr on the brass rim from the HK throwing them 30 yards. They reload ok, the flute is still visible after resizing. I buy military brass (Lake City), it seems to hold up better in the HK. I have a bunch of Winchester brass I keep for the bolt gun. I've added a port buffer with a rubber deflector to the HK to avoid denting and throwing the brass so far. Even with the HK being so ruff on brass, they can be reloaded 12 - 15 times. The first sign of worn out brass is typically cracking in the neck.

Oops, must have already been typing. Missed the new thread.

Edited June 21, 2012 by Cotys

[LKaler]

I feel so stupid asking these questions, but: does the chamber open up towards the read, and does forming the brass to the chamber cause the bulge because of this? Also, if I am neck sizing only will the bulge stop growing as it is already formed to the chamber?

[photog]

All good questions, so no need to feel stupid. Keep that healthy respect for rifle rounds!

That ring can be left on brass near the base by the resizing die. My Lee die leaves a polished looking ring.

My opinion is your operating in safe territory, the brass looks ok, your pressures are below max, all looks good. Also your bolt gun will be way more tolerant of an overpressure load than some autoloader. Many bolt guns have pressure vents on the side of the receiver for just such a thing.