CCI 250 magnum primers-use in place of standard on .308 w/150 or 168 gr bullets?

[kawzak]

I shoot a 308 w/ 1:12 twist, 20 in.bbl I reload Hornady brass, Winchester, etc . I see some reloading data where the magnum rifle primers can be used (with WW746 powder-and some others). However my question is can I use these magnum primers with H-335 or Varget in place of standard rifle primers? without issue? I bought 1000 by mistake. Looked at one box of large rifle (standard) -picked up another(magnum). Will my accuracy suffer? I shoot mostly the 168gr- Sierras BTHP/match bullets, Bergers-or Hornadys A-Max. I do have some free-bee 150 gr sp Hornadys coming in the mail. Any feedback would be appreciated. I live 70 miles away from where I bought these. Not sure they would let me return these anyway. (Cabellas).

 

[ShootDots]

With large rifle primers a "Magnum" primer produces a HOTTER flame for a LONGER time to ignite heavy charges of powder. They can also be used successfully to ignite moderate charges of "hard to ignite" ball powders. That's why Winchester primers are HOT, compared to their "normal" counterparts. Winchester powders are ball powders. They made their primers to ignite their own powders. A magnum primer will most certainly ignite ANY charge in a 308>>and it may work just fine, as far as accuracy is concerned. However, having said that, it is not necessary. If I were shooting a hefty charge of a ball powder, I would FIRST try a Winchester primer, then if that doesn't work, give the CCI 250's a shot! It can't hurt, it just may not help in the accuracy department.

 

[gene pool]

I discovered that my 280 AI preferred CCI 250 magnum primers over the standard 200's for precision accuracy. Both primers produce under a 3/4 MOA groups, but the magnum primers shrinks the group by about 25%, plus they give more consistent groups. Bottom line, you probably won't know for sure until you try them.

During the primer/powder shortage I had to buy some magnum pistol primers instead of the standard pistol that I wanted. I discovered the mag primers gave more consistent round to round velocities in 9mm and .380ACP than the standards. The accuracy was about the same in both.

Hope this helps,
Gene

 

[kawzak]

Good information, Thanks. Do the magnum primers make more PSI if every thing else was the same ?( Bullet, powder charge, brass).

 

[ShootDots]

Good information, Thanks. Do the magnum primers make more PSI if every thing else was the same ?( Bullet, powder charge, brass).

In the case of Large Rifle primers you may very well. So start a bit lower than you would when your load was using standard primers.

 

[kawzak]

Another question would be would/could they affect barrel life with all else being equal? Does the magnum burn rate make for a hotter flame propagation?

 

[ShootDots]

Another question would be would/could they affect barrel life with all else being equal? Does the magnum burn rate make for a hotter flame propagation?

I could not answer that definitively. However, I can't imagine it would account for any significant loss in barrel life.

 

[gene pool]

Good information, Thanks. Do the magnum primers make more PSI if every thing else was the same ?( Bullet, powder charge, brass).

I have only chronograph measured pistol ammo. I don't have the equipment to measure chamber pressures, but I did note that the velocities were, in essence, the same...in some cases the magnum primed produced slightly lower velocities (go figure). With pistol, I never load above top recommended charges. I find that accuracy is usually found at lower velocities.

With my 280 AI, I am shooting close to the maximum listed charge. That is where I found the accuracy I was looking for. But there are zero pressure signs with the primers.

Gene

 

[Terry_M]

I intentionally switched to CCI 250's in my 7mm-08 using a slightly compressed load of RL17 under 140gr projectile just to see what it would do. It made my groups smaller and my velocities more consistent. My previous ES was almost 100fps with every 10 shot string regardless of charge and now I'm getting 40fps ES or less.

I just went back to 168SMK to test them with 250's and low and behold I put 2 - 5 shot groups (@200yds) under one inch. One with 42gr RL17 and one with 42.8gr RL17 with CCI 250's. I say "I went back to" because I had given up on them using the same powder charges and CCI 200's because they were printing 3" groups at 200 when Quick Load said the pressure was right where I should have been getting my best groups. I have not put them over a chrono yet, but my guess is they will be the same low ES that I've been getting from my 140's.

The CCI 250 should work quite well for you.

Terry

Edited to add - It is also 40 degrees for a high temperature here so I will probably be reducing those powder charges as the year progresses. I cannot guarantee that the change is ES is because of the primers it may be the stability of the RL17 in the lower temps and the increased reliability of the magnum primers to achieve consistent ignition in these conditions.

 

[kawzak]

Thanks for all the info. BTW I find RL-15 powder all day long, I have not seen any RL-17 in any of my books. Is it new?

 

[kawzak]

Sorry ,just lookedRL-17 powder up, my bad.