Spanish Mauser 1916

mwjones

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Finally got out to shoot this old girl today! Took me more than a couple weeks to gather all the reloading components, then a week of rain, and yesterday 80km wind gusts, but today worked out great.

Experimenting with light loads and shot a few groups. First loads were 110gr Frontier CMJ, fl sized Federal brass, Federal primers, and 700x powder. Made up some with 9, 10, 11 and 12 grains of powder. 9 grain loads put 5 on a loonie at 25 yards (I wanted to see if it would hit paper) and a 2.5inch group at 50. 10, 11 and 12 grain loads gradually opened up to about 5 inches group size and 4 inches high at 50 yards. The 11 gr had a one case throat crack, and 12 gr had 2 out of 5. 9grains seems the sweet spot, and it recoils like a 30-30.

Second batch was same bullet, primer and brass, with 35, 36 and 37 gr of IMR4895. groups were around the 5" mark for all 3 at 50 yards, but hard to judge because it was shooting about 8 inches high (of or just catching paper). 37 grains of powder had a case neck crack as well.

So I discovered that the sights are probably set for 200 yards. The one thing that i can't figure out is the case throat splitting. It seems impossible that it's from excessive pressure. The primers all look fine :confused: Maybe it's a brass issue? Do i need to anneal my cases?
 
Unfortunately I didn't take the camera with me. I tried to take some pictures of the split case necks, but my camera doesn't have a macro function? It's about 6 years old :S

I'll try to scan a couple of the targets tomorrow. They're in my ammo box downstairs, and i'm simply too lazy to do it now :)
 
Neck cracks generally are a symptom of hard brass, brass that's been used too much (and thus has hardened), a gigantic chamber, or all three. If the neck is not overly swoollen, then the problem is with the brass.
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All the brass are once fired. I was thinking that it might have something to do with a 7.62 chamber having a longer throat than .308?
 
LENGTH of your chamber won't make any difference, friend, but DIAMETER does.... and so does hardness of the brass. Brass hardens simply through aging, which is why there is so much really old ammo around with split necks.

Best bet is to anneal your case-necks lightly. Just heat them up a bit with a propane torch on the edge of the sink and when the brass starts to blue, tumble them instantly into a sinkful of cold water. Works.

Have fun!
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You did'nt mention how many firing/re-sizing cycles are on the brass that you are using. Brass that has been fired/re-sized many times will work harden and be prone to splitting at the neck. I'd try some virgin brass and see how that works.
 
Yes, it is a 7.62 conversion. All the brass is once fired federal brass. I can't see any signs of it beign annealed before, so maybe i'll give it a try. I don't think they're that old. I resized about 9/10 of the case (die about a full turn off the shellholder) and used a light roll crimp.

If it is just junky brass, i'm ok with losing 2 or 3 out of 50. I have about 650 to go through before I buy some Lake City or get a primer pocket swaging die for my empty IVI brass.
 
All the brass are once fired. I was thinking that it might have something to do with a 7.62 chamber having a longer throat than .308?

The only difference is in thickness of brass! Please do not create a new myth. The rifle itself may have a different throat dimension but that has little to do with the accepted specs for the load in service!
 
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