Large Rifle Magnum Primers

[stagpanther]

Not writing this to start a whine-fest--just a simple (hopefully) question. My supply of large rifle magnum primers is coming to an end, probably run out by the end of the year. I shoot lots of hand-loads that require them--I've read that CCI's #34 is the same thing as a LRMP with (perhaps ? ) a slightly thicker face to help prevent slamfires. Has anyone used CCI # 34 in place of LRMP and found they perform identically (especially in large volume cases 75+ grs.)?

thanks in advance.

[ligonierbill]

I've been using CCI #34 in place of 250s for some time, and I have yet to see a difference in performance. Now, I mean a noticeable difference; have not run a side-by-side comparison.

[stagpanther]

I've been using CCI #34 in place of 250s for some time, and I have yet to see a difference in performance. Now, I mean a noticeable difference; have not run a side-by-side comparison.

Thanks--I know you shoot some big magnums; I guess what I'm looking for is some notion that reliability, safety and accuracy are more or less on par when used in big cases like RUM's, large weatherbys, 338 LM etc. I have a couple of bricks of CCI #34, and I think I've seen them pop up once or twice during the great component recession.

[MarkCO]

Reliability didn't change for me.

Going from Magnum to #34s, my SDs went up. Velocity change was minimal if at all.

[jmr40]

Winchester large rifle primers have a reputation for being a pretty hot standard primer. If I couldn't find magnum primers they would be my 2nd choice.

I no longer have it, but I used them in a 300 WSM and got identical speeds and accuracy compared to magnum primers. That doesn't exactly answer your question but is the closest info I have.

[stagpanther]

Guess I'll give them a go and see what happens.

[Shadow9mm]

Call cci and ask.

I did this several years back in relation to 450s and #41s. Cci advised the primers were identical except the anvil angle for the #41s was changed to make them less sensitive.

If i had to take a guess id say their relationship with large rifle size primers is the same. But the only way to know for sure is to call and ask.

[akinswi]

Originally Posted by stagpanther

Not writing this to start a whine-fest--just a simple (hopefully) question. My supply of large rifle magnum primers is coming to an end, probably run out by the end of the year. I shoot lots of hand-loads that require them--I've read that CCI's #34 is the same thing as a LRMP with (perhaps ? ) a slightly thicker face to help prevent slamfires. Has anyone used CCI # 34 in place of LRMP and found they perform identically (especially in large volume cases 75+ grs.)?

thanks in advance.

Stang, I found no difference between the 250s and the 34s in my M1 . The 34s are extremely hard to find And I don’t under stand why they are typically $20.00 higher than the 250s.

Of course 30-06 biggest cartridge I reload for , I dont have anything remotely close to 75 plus grain cartridges

[Unclenick]

When The Rifleman's Journal was still up, you could find some primer testing (the Wayback machine still has it). With LR, it didn't generally make a dramatic velocity or pressure difference. With SR there is more difference in some tests, up to the equivalent of about 5% of the powder charge in one test Charles Petty did in Handloader in 2006. That was with a 55-grain V-max in a 223 using Reloader 10X. It ran 3150 fps from a bolt rifle using Federal 205 primers, which was the mildest primer he tried, and 3300 fps using the hottest primer he tried (I've forgotten which one that was, as it was awhile back). Anyway, in QuickLOAD that a velocity difference is also generated with about a 5% increase in powder charge in a 22" barrel.

Another situation that can arise is SD can be lower with a standard primer when the case is pretty well filled with powder but then be lower with a magnum primer when the loading density is low. The magnum primers often do better with Garand loads, which are notoriously low in loading density. But it depends on the powder choice, too. There isn't a fixed rule about it.

[44 AMP]

I've never used them, but always heard that CCI #34 were standard (not magnum) primers made with thicker cups to GI specs.

CCI would be the people to ask, I think...

[Marco Califo]

#34 are responsible for igniting USGI Ball powder in 7.62x51 cartridges. They are in fact, hotter than standard primers and the formulation and quantity of the priming compounds was tailored to the Ball powder in use: BL-C(2). They are considered to be magnum primers.

[akinswi]

The 34s actually lite the wC846 powder I used in 303 british better than the 250s.

I would occasionally get a delay with the 250s never had a delay with 34s.

[stagpanther]

Well, I decided to "go bold" today and loaded up a random test load for my 7mm STW using new powder and new bullet I'd never tried before in it--73 grains of R 19 and 150 gr ballistic tip lit up by the CCI #34. I also took the muzzle brake off the 28" barrel--while it did a good job of reducing the felt recoil it also was hammering me with concussive report; I'm getting worried about turning my brain to jelly with big magnums with muzzle brakes and have removed most of them. The felt recoil is no worse than that of a 7mm RUM without brake which i find tolerable. I regret that I did not bring the labradar out, but I just wanted to do a "quickie" for impressions, I'm happy to report that I didn't see or feel any abnormal performance--in fact once I found the range on the target the remaining impacts were well under MOA at 254 yards.

Thanks for the input.

[stagpanther]

I would occasionally get a delay with the 250s never had a delay with 34s.

I get those every now and then in really big cases--especially if I'm using a fine spherical and I start with a load that is under say 90% +/- powder capacity.

[akinswi]

Originally Posted by stagpanther

I get those every now and then in really big cases--especially if I'm using a fine spherical and I start with a load that is under say 90% +/- powder capacity.

yep the delay reminded me of shooting a Flint lock …. Click…. Boom.

Glad the 34s did well good luck finding more. I sign up for alerts and buy them as soon as I get alerted

[Unclenick]

CCI told me their #34s are identical to their 250s except for the anvil shape that reduces sensitivity to military spec level. Winchester claims their #34s are the same primers they make for the Lake City ammunition plant. Given that military primers are expected to work down to -65°F, I expect they are magnum as well.

CCI #41 primers are the same as their #450 except for the anvil profile, and so are magnum primers as well. Again with Winchester, they claim their #41s are actual Lake City-type primers.

Federal GM205MAR are military-sensitivity spec primers for the AR, but they are not magnum primers. Rather, they are 205M match primers assembled into a thicker cup to reduce sensitivity to military spec levels.

[stagpanther]

Handy info unclenick.

[std7mag]

Stag,
From my experience shooting the 7mm Rem Mag, 7mm WBY Mag, your use of RL19 & 150gr bullet, will give you a "reduced" recoil round when compared with other powder & bullet weights.
It will certainly get the job done, no doubt!
But your not getting the velocities that the STW is capable of.
Not compared to say RL26, IMR 7828, or Ramshot LRT.

That being said, I've had zero issues using standard large rifle primers in the magnums with any of Alliant's Reloder powders.

There are articles where standard large rifle primers actually bring down the ES/SD numbers in Magnum cartridges.

If you really want impressive, try some 180gr bullets with RL33!!

[stagpanther]

If you really want impressive, try some 180gr bullets with RL33!!

I have, with 180, 183 and 190 gr bullets. RL 33 tends to foul my bore quickly so accuracy tends to be temporal, a few go in well in then it scatters.

Note that I'm using the RL 19 paired with the 150 expansion tip; Nosler's solid. Even at just 350 yds--which is about as far as I can reach at my neighborhood range, there is a big difference in bullet drop, and my shilen barrel seems to like them--I can pretty much drive any size bullet to around 3200 fps, so it becomes a question of "how fast do I really need it?" which is a direct corollary to "how fast do I want to burn my throat out?"

My biggest issue with the 7mm STW is getting it to work in my Accuracy International CIP 3.850 magazine (about $150.00 from Mile High). I've been bubba-tizing it all weekend and am very close to either success or ruining it. The case belt sure causes a lot of problems.