CCI # 34 primers and cast boolits?

[exile]

My understanding is that cci # 34 primers are considered magnum primers. Taking that into account, would they be safe to use with the reduced charges normally associated with cast boolits, specifically, for example, a .308?

Thanks in advance for your thoughts.

exile

[JimB..]

Yes

The magnum primer may not be necessary depending on the powder you use, but it’s not going to make a low to medium charge dangerous.

As with any other time you change components, start low and work up.

[georgerkahn]

After being ~10 feet away from a M1 Garand blow-up where a seasoned loader had done all correct in his reloading -- 'cept his using Federal primers -- I marked all my unfired (CCI large rifle) primed '06 rounds with a Sharpie; mail-ordered some #34 primers; and.... have used NOTHING ELSE in my Garand. The "purpose" of the large-primer replacement -- the CCI #34 -- and, the small- replacement -- the CCI #41 -- is for the cup to need a significantly greater impact to detonate it -- what is safety-required for pretty much all "gas guns"!
I mirror what JimB.. posted here above, adding that these primers (#34 & #41) are, imho, a requisite for any and all gas gun loading. You did not note if your ".308" is, say, a Garand -- where, again, I'd go with the #34.
When I made the switch from plain-Jane commercial primers to the #34's for my M1 shooting, I did not alter my powder at all. However, note too that all my Garand shooting was "target" -- using published and proven loads complementing the op rod/spring action of this great rifle.
geo

[Larry Gibson]

I use #34 primers in several cartridges, including the .308W, with cast bullet loads. They work fine and since most of my loads were worked up with WLR primers I have found little difference in velocity or pressures in cases with .308W to 30-06 capacity using medium burning powders such as 3031 - Varget in burning range. With faster pistol powders in such cases there can be a slight increase in psi so if those are the powders used then readjust or tweak the load for accuracy with the #34 primer.

With normal already worked up cast bullet loads in such rifle cartridges the substitution with the #34 primer or any other magnum primer will not result in any disasterous increase in pressure.

[swheeler]

After being ~10 feet away from a M1 Garand blow-up where a seasoned loader had done all correct in his reloading -- 'cept his using Federal primers -- I marked all my unfired (CCI large rifle) primed '06 rounds with a Sharpie; mail-ordered some #34 primers; and.... have used NOTHING ELSE in my Garand. The "purpose" of the large-primer replacement -- the CCI #34 -- and, the small- replacement -- the CCI #41 -- is for the cup to need a significantly greater impact to detonate it -- what is safety-required for pretty much all "gas guns"!
I mirror what JimB.. posted here above, adding that these primers (#34 & #41) are, imho, a requisite for any and all gas gun loading. You did not note if your ".308" is, say, a Garand -- where, again, I'd go with the #34.
When I made the switch from plain-Jane commercial primers to the #34's for my M1 shooting, I did not alter my powder at all. However, note too that all my Garand shooting was "target" -- using published and proven loads complementing the op rod/spring action of this great rifle.
geo

Follow this^^^^^^^^^^^^^^^ you'll be fine.

[exile]

Thank you all for your responses, I am encouraged.

exile

[winelover]

CCI #34 primers are $8/brick, more than CCI LR..........close to 25% more costly. Use them if you think you must. However, all gas guns do not require them. I have shot thousands of CCI LR in my Armalite AR-10 without issues. It all depends on construction/design of the firing pin.

Winelover

[Larry Gibson]

"After being ~10 feet away from a M1 Garand blow-up where a seasoned loader had done all correct in his reloading -- 'cept his using Federal primers"

Makes one wonder how in the heck a bajillion rounds were fired in M1s and MGs from the mid '30s through WWII, Korean war and the Viet Nam war not to mention the bajillion rounds fired in M1s by match and casual shooters throughout the years prior to the introduction of #34 primers......

Makes me wonder how there can be any M1s left...... should have all been blown up by now having been shot without using #34 primers...….

I also am amazed I'm still alive having shot so much 7.62 NATO (M118, SB M118, M852 and m118LR) loaded with Winchester and Federal primers as to have shot out several M1A/M14 barrels how is it I never blew one up? Guess I'm just lucky...….

[JimB..]

I’m starting to detect a bot of sarcasm in this thread.

I think that the #34 and #41 primers are a little harder to fire than most other rifle primers, and that probably reduces the risk of certain types of failures. Some folks are more cautious than others, some of you check 3 sources for loading data, others don’t own a single manual, it takes all kinds.

[gumbo333]

Not trying to be too sarcastic but I'm certainly glad Larry Gibson hasn't blown himself up. I have gain a tremendous amount of knowledge from him and many, many others on this Castboolit forum. I've never shot a 34 or 41 primer, thankfully.

[30calflash]

I think the op has little to worry about with using the #34 primers in his planned reduced loads.

FWIW years back during the first? primer shortage when there were none to be had, CCI #34's were the first available at the shop I worked at. Had never heard of them so I called CCI.

Their tech rep stated that they were magnum LR primers with anvils that were shorter than std mag primer anvils. .004 IIRC. This was for use in service rifle loads so they were less sensitive then std LR or LR mag primers used in handloaded ammo.

That's the reason for them, I've not used them yet but will someday. I haven't had issues in using any LR primer seated in a clean pocket when used in a safe and clean USGI service rifle or clone.

[swheeler]

They were introduced to stop slam fires in certain guns. To the OP they will work just fine in your reduced loads. If you are substituting the #34 in a load you already developed with a std primer it may shot different, you'll have to adjust the powder charge.

[Peregrine]

I standardized on them, they're all I use for large rifles. Originally I was just concerned about slamfires in semi autos, but I have found with typical cast boolit loadings using H4895/2400 they give greater consistency. I'd expect that would be the case for most powders with a low load density, but those are the two I gathered data for while inter changing primers.

They also produce a little extra velocity, the only time I'd be hesitant to use them is if I had a max load worked up with standard primers and needed to switch to the #34 for some reason.

[exile]

Great information! Just as a matter of historical curiosity, what were the primers used in 30/06 loads in WW II like? I know they were corrosive, but what other characteristics did they have? Were the same primers used for bolt-action rifles, BAR's, machine guns, etc.,.?

Thanks,

exile

[fastdadio]

I use the #34 primers for loading my 30-06 Garand, and .308 M1a. Simply because I have read too many first hand accounts of slam fires with these rifles. These rifles have free floating firing pins, and in some cases the inertia of the pin as the bolt travels forward, has been the suspected cause of out of battery firing, with catastrophic results. I have not read of this happening with any other type of rifles. Having loaded thousands of rounds for my rifles using standard primers without mishap, I consider the extra cost of these #34 and #41 primers to be cheap insurance, and decided to start using them. I would also go so far as to say, if one is not reloading for an M1, there is most likely no need to use the hardened primers. Here are a few links on the subject that are sure to consume one till the end of time;
https://m14forum.com/steel-wood/7968...incidents.html
https://m14forum.com/steel-wood/1660...-happened.html
https://m14forum.com/m14/121190-m1a-slam-fire.html
https://www.ar15.com/forums/armory/B...now_/6-453467/
http://www.leatherneck.com/forums/sh...-M1A-Slam-Fire

[Larry Gibson]

The point of my bit of sarcasm is to point out that billions of rounds have been shot through M1s and similar actions w/o any problems of "slam fires" well before the use of CCI #34 primers. Every time we hear of a "slam fire" it is with reloads and everyone swears the reloader could have done nothing wrong..... such is most often not the case when actually investigated. Reloaders used millions if not billions of Winchester, Federal, Remington and CCI primers in Ms, M14/M1As, M1 Carbines and similar actions etc. with out a "slam fire" caused by the firing pin hitting the primer well before the advent of #34 primers..

So lets look at all of those actions; for the firing pin to reach the primer the bolts would have to be rotated into locked position. Thus if the primer did detonated the primer the rifle would simply function as normal and a "double" would have occurred......not a catastrophic failure. If a catastrophic failure occurs when the bolt is locked then something other than the brand of primer is amiss. If the primer is not seated correctly and detonates pror to the bolt locking (from the face of the bolt smashing into it, not the primer hitting it) then is that the fault of the primer? No it is not, it is the fault of the reloader for not seating the primers correctly.

I was on a range when an SKS supposedly had a "slam fire". Everyone blamed the use of WLR primers. However close inspection revealed 2 of the rounds left in the magazine had high primers. The shooter (not injured) admitted he had just gotten a Hornady progressive press and those 7.62x39 cartridges were the first rounds he had loaded with it the night before. He further said he just assumed all were correct and did not inspect the cartridges. Looking at the remaining rounds in his ammo box also showed several with high primers. Would the use of #34 primers have prevented the slam fire? Maybe, maybe not...… point is the fault was with the reloader, not the primer.

Let us also not forget that rifles of any type are simply a machine and things can go wrong but unless in firing pin cam/block in the M1s receiver is damaged the firing pin can not hit the primer unless the bolt is locked into battery.

I have about 10K #34 which I got before the Obama rush when they were less than regular CCI 200 primers. They work fine with cast bullet loads. I'm not saying not to use #34s if you want. What I'm saying is no need to disparage other primers when, in fact, they have and still work fine when used properly. When used improperly it is not the primers fault but the users fault.

[madsenshooter]

#34s are what I use in all my LR primered rounds. the only reason is because I got a bunch from a gunstore closing. I couldn't tell any difference between #34s and CCI 200s in my loads. I have had a slamfire in an M1A using Federal BR primers. I'd fully chambered a round by hand, then let the bolt fly forward. I nearly shot my front tire! I didn't have any problems with them during regular cycling, but quit using them in the M1A after I'd shot what I already had loaded.