To finding my actual hunting load this year. Here's the closest so far.
270 WSM
135 SMK (sierra match king)
IMR4350 58.0gr
WLRM primer
RP case.

100 yards:

The only "problem" I had with the above load is, its .7 grains lower than the recommended starting load from sierra. They recommend 58.7 starting load. The "problem" I had was on 2 of the rounds, I got powder residue around the primer. My assumption is there wasnt enough pressure to "seal" the case to the primer upon ignition. The 3rd case looked fine. These were RP cases, once fired, trimmed to length. Same cases, same lot# showed NO leakage as powder charges went up to 60.0 grs as a max is 62.7. Primers were Winchester Large Rifle Magnums. Now, I have read on the internet that winchester had some LR primers that were .0005 undersize. (you can believe everything you read on the web ). I miked the primer pocket, they all were .209". I'm going to assume leakage was due to a light charge and bump up the starting charge accordingly. Any other thoughts? Oh, I am going to mark the 2 cases with a magic marker to see if they leak again.

Oh, the reason I started at 58, is thats the starting charge that IMR recommends on their website. Sierra starting charge 58.7, IMR 4350 starting charge 58.0. Bad primer pocket?? Undersize primer?? Too light of a charge??

First...Why a "match King" and not a "Game King" bullet?

Second...I have never "miked" any primer pockets. I have always gone with how it felt when I seated the primer. If it slid in like it was greased then I discarded the case after removing the primer. If you felt a bit of a tug when you seated the primer all is good. However, if you had soot around the primer after firing then I would look for some other problem. If it was an under sized primer you would have felt it [or not] when you seated it. It's posible that one or two cases had a shoulder pushed back when resizing or the bullet was jamed [hard] up against the rifling leeds. Usually a sooty primer indicates an over pressure problem.

Third...If indoubt as to the quality or condition of the two offending cases...Just toss them.

Bushy, I used a matchking for load developement cause they are a lot cheaper than my hunting bullet, barnes TTSX. I can get close with the SMK then lower the powder just a bit and work on the barnes. I'm already close with the SMK and then just fine tune it with the barnes. Basically saves $$$$$.

I agree, match kings are not designed for game animals only for targets. Its possible that the load was under pressure, how were the necks? Any sign of carbon around the neck? Get the bullet your going to be using for the game your hunting and work up the loads.

Necks were sooty, shoulder clean. Damn, wish I would have taken a pic of the cases before I cleaned them.

A sooty neck is normal.

A quick premer on cartridge movement in the chamber when the firing pin hits the primer. 1. pin strike and the case moves forward. 2. Powder ignites and the primer backs out a bit. 3. Pressure builds and the case SLAMS back against the bolt face and reseats the primer sometimes smashing it. 4. Case expands to grip the chamber wall. 5. Bullet exits the case mouth. 6. Case relaxes for extraction from the chamber.

This may help in diagnosing your problem...Maybe.

When I shoot H380 out of my 22 250 the necks are badly "sooted". It's not a dimensional issue with my rifle and casess since when I shoot Varget or IMR 4350 there is considerably less soot. In my case it's the nature of the powder.

I twist some 000 steel wool around the neck a few time then place in the tumble or US and they come out clean. If these cases have been fired alot of times it could be that they might need annealing.

If these are new cases, go ahead and shoot em and maybe up the powder charge a wee bit at a time. Have you run these loads across a chrony?

Didnt use my chrony. I usually dont until I find a good group. I find if I use the chrony all the time, I'll usually run after velocity which is not what I want to do. I'll be in the reloading room in a little bit, I'll post after then and let yall know if the primer pockets are loose with the new primers. I'm still leaning on just a low charge, letting a little gas thru the primer pocket until the case pushed the primer back in. Just like bushy explains in #2.

Cabron or grit in the pocket, poorly seated cap, cap or case anomily. Either way, pinch the neck and toss. If hi-pressure gas got by once it might do it again due to flame etching and that aint a case I'd use.

Nice group BTW! Keep it up!

Here is a pic of a affected case. Its on the left. It looks like a half moon cut or impression made by primer seater. I hand prime and I dont think I could have used enough force with my thumb to cause the damage. But by george, thats where the gas leaked from. You can see where the gas leaked in the pic, case on left. Take a look at the pics.

Pinch that neck and give it the heave-ho!

Check yer bolt face for shmutz too.

stovepipe wrote:

Pinch that neck and give it the heave-ho! Check yer bolt face for shmutz too.

fer sure. already in da trash can. had a carbon ring on the bolt face, already cleaned it up.

Good to go, back to testing Mr. Man!