Cast bullet question: 7.62x39 (SKS)

[verzilli]

Guys,

Have a basic plinking load of 10 grs Unique with a 150 gr Penn Bullets lead bullet, made for a 30 cal, sized to .312.  Lyman manual says 12-15grs of Unique.

I think I have a pressure problem.  I have to whack the bolt to extract the case, and the primer is cratered.  I don't know what the seating depth (OAL) should be for this bullet.  Lyman says OAL 3.03" which seems inordinately long.  If i do that, there's almost no bullet in the case.  I assume I have set the bullet too deep, which is causing a spike in pressure. 

Do I find the OAL (bullet depth) by experimentation?

Thanks.

[Dand]

If you have seated the bullet too deep you may have a pressure problem. Is your bullet a Lyman design or very close?

Have  you tried contacting Penn for their recommendation?

I'd try seating them as far out as possible per Lyman, maybe use an uncharged case and see if they will cycle thru the action and experiment.

Don't want them sticking in the throat either.

Is your brass the same as Lyman's?  Do your cases take the small or large primer?  I think you can find cases with different primer pockets. What case and primer did Lyman use - vs what you used?

Good luck. I haven't shot any cast in my SKS yet but have the molds and have some 100 gr Hunter Cast bullets I want to try.

[Lloyd Smale]

if your trying to get a cast bullet to run the action on your sks you should think on trying a slower powder. Something like 1680 or 2230 would work much better. Even 2400 would do a much better job the unique will. Running max pressure with a fast burning powder using cast bullets has a few problems one is that it burns a bit hotter and leading can result if your not using a gas check and also the fast smack that unique will give your bullet will tend to deform it if your not using a very hard alloy and accuracy will suffer. Id switch to 1680. Look in your loading manual and use the lowest powder charge for it they list and then work down to your bolt quits ejecting the case and then go back up till it just runs reliably. Verilli going with 100 grain bullets isnt a good thing either. A bullet that light will really need to be pushed to run an action. For cast in the sks i wouldnt go lighter then about a 130 and 150-160 would be better yet.

[verzilli]

Thanks for the input guys.  I'll "speriment.  BTW, I am using 150 gr bullets, not 100 gr., and I was using reduced loads from a Lyman manual.

[Lloyd Smale]

Sorry but i would never run a 150 with even 10 grains of unique. My normal load is 8. As to lyman pushing them with 15 thats the level i load 2400 to. Like i said in my earlier post if your running cast in your gun and you want it to run the action DONT use fast powders. Its hard on the bullets and hard on the gun. Run them with the same powders listed for jacketed bullet starting loads and you will be in the ball park. You can even go from there and back them down a bit as long as the action runs. Unique is a decent powder for light plinking loads. I load 7 grains of it with a 130 to use in my ruger bolt for the grandkids. But it wont even come close to running an action. To many people that really dont know try to use powders that arent appopriate for what there trying to do just because they have some or are to cheap to buy the right powder. Powders like 4227 1680, re7 2230 are what the 762x39 run best on, cast or jacketed.

[verzilli]

Thanks Lloyd.  I pulled the bullets out a bit and the pressure signs did lessen.  Extraction was easier.  But I think your 8 gr load is better, and I"ll try that.  Have you ever used the Lee bullet (designed by CE harris?) for the SKS?  155 gr and 160 gr, I believe.  I mould for my 44 mag and love it. 

[Steve P]

You might want to think about position sensitivity and primer also.  Both will make a difference.  I use 8.0 grains of Unique with a 145 cast bullet from a .223 case and use 12.0 grains with same 145 out of .307 or .356 case.  Both fireform my brass and I have no pressure problems.  Not a semi-auto tho either......

Steve

[Lloyd Smale]

sorry but no experience with that mold.

Thanks Lloyd.  I pulled the bullets out a bit and the pressure signs did lessen.  Extraction was easier.  But I think your 8 gr load is better, and I"ll try that.  Have you ever used the Lee bullet (designed by CE harris?) for the SKS?  155 gr and 160 gr, I believe.  I mould for my 44 mag and love it.