6.5 Creedmoor Over-pressure

[Swaim13]

I was shooting my 6.5 Creedmoor on Sunday and had a few primers break. This was the 3rd time using the brass. My load was Hornady 147 gr ELD-match bullets, 38.5 gr H4350, Starline SR brass, and WSR primers. I am seating the bullets slightly long so that I am 0.02 in off the lands. I had done load development on the first load with the brass and had gone up to 39.5 gr of powder without any signs of over pressure or primers breaking. I did not clean my primer pockets between firings but there was not much in them and the primers were all seated below the edge of the brass so that it was tactile.

I am wondering if I am using the wrong primers for 6.5 Creedmoor, the primer pockets needed to be cleaned, am I dealing with some carbon fowling, or I missed something when doing my load development. I was hoping someone here might have some thoughts.

Is safe to keep using this brass or should it be replaced?

I have attached a few photos of my brass and the hodgdon reloading data to help.

 

[BradMacc82]

I'd switch primers, appears that the Winchesters didn't pop due to pressure (judging by the radius on the edge of the primer), but due to firing pin protrusion or weak cup.

*Although I do see a bit of an ejector swipe on the rims though, so that does make me question my previous statement some.

Personally, I haven't noticed much of a difference between shiny clean primer pockets or slightly fouled pockets, I normally get a few loadings out of a case before I'll take the pockets and clean them out - as long as the flash-holes are unobstructed, I'll let it go for another loading or two.

I'd give the rifle a thorough cleaning, I shoot .260 - and that is known to develop a hard carbon ring in the chamber/throat - and that can raise pressures if it's not addressed. Not sure if 6.5CM is also prone to that, but it's a thought.

 

[Speed3]

I've run 40.1 gr of H4350 powder at mag length and never seen what you're seeing. Lapua sp brass using CCI BR4 primers

If it were me, id suspect carbon ring. Ejector swipes are there which is interesting at that powder charge.

I've fired brass 10 times and never cleaned primer pockets, doubt that is the issue.

If you're close to Frederick I'll give you some BR4 primers to try.

Factory barrel? Didn't happen the first 2 times load testing? Did you check/calibrate your scale? Grab wrong powder?

 

[BradMacc82]

OP, how long has it been since you've cleaned the rifle?

 

[Swaim13]

I am hoping it is a carbon ring issue. I have been using Hoppes Benchrest 9 to clean the rifle. I have never had any carbon ring issues with other rifles in the past so this issue was new to me. I am a little worried as I am also seeing the rings on the sides of the brass in addition to the ejector swipe (photo 1). I use these same primers in my Remington 700 in 223 which hits primers stupidly hard (craters even factory ammo) but have been told that the firing pin hitting that hard is ok.

This is the factory barrel on a Savage stealth 10 BA. I had one primer break in the 150-200 shot range. I chalked that one up to being a fluke. I got three that broke in rounds 250-300 through the rifle. That was a bigger red flag to me. I clean the rifle every 100-200 rounds.

I use a RCBS Chargemaster lite and let it warm up for 20 minutes then calibrate it every time I use it. I can also confirm that the powder was H4350. Smell is different from Varget which is the only other powder I use.

Do you think the brass safe to use once more if I clean out a carbon ring? (Not sure if there is one yet) Any tips on cleaning out a carbon ring?

 

[BradMacc82]

For me, I've been using the Hoppe's Elite (foaming) cleaner - and a stiff brush (can't recall if it's brass or bronze). Pump about 3 shots of foam into the chamber, let it sit for roughly 5 to 8 minutes with the muzzle down while working from chamber to muzzle. Seems to do the trick perfectly for me. After a few passes with the stiff brush, I normally have clean patches after the 3rd to 4th pass. Haven't had any issues since E.Shell educated me on that quirk of the .260Rem.

Knowing about the carbon issue, I normally don't go more than 150 rounds before doing a solid cleaning.

If the bolt wasn't stupid hard to unlock, and the brass slips into a shell-holder w/out any significant effort - I'd think it'd be safe to say the pressure didn't get high enough to swell the case head/rim, and it'd be safe to use that brass as a 'plinking' batch. But, if in doubt - throw it out. The most expensive brass is still a hell of a lot cheaper than your safety.

 

[Speed3]

For carbon wipe out is one if the best, I used it forever. Spray it and let it soak over night. Make sure the muzzle is lower than the action so the gunk doesnt go into action. Get a good nylon brush and scrub it 15 times or so and then run patches till clean. Rinse and repeat if patches aren't clean.

300 rounds through the gun in total?

Case head separation sucks, agree with brad when in doubt throw it out.

https://www.midwayusa.com/product/1...ss-foaming-bore-cleaning-solvent-5-oz-aerosol

 

[Swaim13]

When I go out I typically shoot 100 rounds. The brass where the primers blew were difficult to get out. The other pieces of brass came out easily. I looked at the first 50 shots I fired and there were no problems pressure wise. I ordered some new brass and will likely trash this set of brass just to be safe.

I have put 300 rounds down the barrel but bought the gun used. I do not know how many rounds have been down the barrel total. I clean my guns every other time I go to the range which means around 200 rounds down the barrel between cleanings (except for my 22s which I let go a little longer) but will do this gun after every time I go from now on.

I am glad that this turned into a learning experience for me and no harm was done. Thanks for all the help!

 

[Uncle Duke]

OP, you should not be anywhere near blowing or piercing primers with the load data you specified. You should also not fire that rifle without knowing and correcting the exact cause of what you describe.

If I were you OP, and especially not knowing the history of that rifle? I'd have it checked over from butt to muzzle by competent gunsmith.

Yes, you could indeed have a carbon issue. You could also have a headspace issue, a chamber issue, a firing pin issue, a bolt face issue now that it's been subjected to high pressure blow back.

 

[Squaregrouper]

Look into the case volume of Starline brass. The differences between brass manufacturers is significant. I gave up on high dollar Peterson brass because of issues similar to yours. Increasing charges by .2 grain and all of the sudden the pressure and fps skyrocketed, the bolt was hard to open and there were craters and brass swipes- just from a .2gr increase over a mild load.
I use Win LARGE primers, and don't have any 6.5CM w/SRP experience.