Ball powders - magnum primers

Jimbeaux82 · Sep 28, 2015

Dr Mike,

In another post I have detailed my attempts to develop a Gold Medal Match Clone for 308 using 168 gr and 175 gr bullets. While I have not mentioned it , I am also concurrently trying to develop a 5.56 mm NATO Mk 262 Mod 1 clone load (77 gr NCC OTM, 2700-2750 fps). One of the powders I have on hand in quantity , and am testing for the clone loads , is AA 2460, which is a ball powder. When testing the original loads I tested, I used conventional military primers, CCI 34 and 41 for this powder. When I re-read the load manuals, I saw where mag primers were recommended for this powder. Do you think I need to re-shoot the loads with mag primers? Also, regarding reshooting the AA2460 with a mag primer, do you think that has potential to tighten up the groups? I know ball powders require mag primers particularly in cold weather but I have read where mag primers usually slightly open up the groups. Since I was shooting on a 90 deg day, and Louisiana temps seldom get below 30 deg, and these are not magnum charges of powder, may not need the mag primers for reliable ignition. I would like your opinions on this.

Thanks,

Jimbeaux

baltz526 · Sep 29, 2015

The Chronograph will tell you. If your getting consistent velocity Standard primers are fine. I use a lot of H414/W760 and use Magnum primers with it in 22-250, 243, 308, 30-06. But in 223 I tested it with standard primers with the 64gr Winchester Power point. It worked fine at max capacity under the 64gr with a tight Lee crimp.

DrMike · Sep 29, 2015

Jimbeaux82":36f2fxvk said:
Dr Mike,

In another post I have detailed my attempts to develop a Gold Medal Match Clone for 308 using 168 gr and 175 gr bullets. While I have not mentioned it , I am also concurrently trying to develop a 5.56 mm NATO Mk 262 Mod 1 clone load (77 gr NCC OTM, 2700-2750 fps). One of the powders I have on hand in quantity , and am testing for the clone loads , is AA 2460, which is a ball powder. When testing the original loads I tested, I used conventional military primers, CCI 34 and 41 for this powder. When I re-read the load manuals, I saw where mag primers were recommended for this powder. Do you think I need to re-shoot the loads with mag primers? Also, regarding reshooting the AA2460 with a mag primer, do you think that has potential to tighten up the groups? I know ball powders require mag primers particularly in cold weather but I have read where mag primers usually slightly open up the groups. Since I was shooting on a 90 deg day, and Louisiana temps seldom get below 30 deg, and these are not magnum charges of powder, may not need the mag primers for reliable ignition. I would like your opinions on this.

Thanks,

Jimbeaux

I'm late to the party, Jim. Distracted by too many irons in the fire. The magnum primers will increase pressure, and the increase can be significant if you are already tickling the dragon's tail. To be on the safe side, I do recommend that you drop back about five percent and work up to verify that the load is safe. I have never noted that magnum primers open up groups. If anything, they tend to increase pressure (and hence, velocity) which results in slightly tighter groups. Even in Louisiana, the magnum powders can ensure complete ignition in your powder column with a ball powder. In short, yes, I would use the magnum primers and I would drop back five percent and work up. Let us know how this works for you.

bigedp51 · Sep 29, 2015

CCI 34 and 41 are magnum primers

•Mil-spec sensitivity
•Initiator mix optimized for ball/spherical propellants
•Available in large (No.34) and small (No. 41) rifle
•Use the same data as CCI Magnum primers
http://www.cci-ammunition.com/products/ ... aspx?id=30

Know thy rifle..................and the reloading components you use.

Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain.

The powder was changed to the single base IMR-4064 because the previous powder RL-15 a double base powder was too heat sensitive in the heat of Iraq and Afghanistan.