I primary use IMR 4064, IMR 4895, and AA & IMR 4350. I still have kegs of AA2520, a ball powder blended to have a pressure curve match with IMR 4895. CCI #34's work fine with all these powders.
Slamfires are real, and according to CCI, the #34's are their mil spec product line. They are less sensitive than the commercial primers, and so, they will slamfire less often than commercial primers. Once you experience a slamfire in an semi automatic mechanism, it will really startle you, and safety gets moved to the top of the priority list. Lots of outstanding scores have been shot with military NM ammunition, and NM ammunition with the older 174FMJBT removed, and an 168 SMK placed on top.
If you found a powder combination that does not work well with #34's, well, don't use #34's. So far, my #34's are doing well with everything I have on the shelf, and I have had slamfires, and am doing what I can, not to have more.
Again, I'm not saying #34's won't work... they certainly do, and, as I mentioned, it's what I use for my semi-autos. I quit using them for my accuracy handloads for my bolt gun, however, based on my own experience with accuracy testing... that is just my specific experience. I will likely not use #34's for the very few accuracy loads I work up for my M1a.
I also hear what you are saying about slamfires... safety should always be at the top of the list when preparing a handload. Yes, #34's are there to help prevent slamfires, etc, but, as you mention, the real purpose (in surplus ammunition) is to get the rifle to go bang even in extreme environments. The tangential issue with military ammunition would be it's use in machine guns, which introduces other considerations and remedies... like staked or crimped primers. As far as using standard primers in semi-auto handloads, proper brass prep is one of the keys to safety... making sure any primer, including #34's, et al, are seated flush or below flush is paramount. Making sure the rifle is serviceable and not worn or damaged... and particularly the M1/M1a family... is another.
The closest I have in a comparison of CCI#34’s and WLR is with the 30-06 data. And based on my data, I would say the WLR is “hotter”. If the CCI #34 is a magnum primer, the WLR is more of a magnum primer, at least using velocity as a guide.
Just because a primer is 'hotter' does not directly correlate into higher velocity. My first tests between standard and Magnum primers was with a standard load of H335 in 5.56mm. Although my Speer manual recommended a Magnum primer for H335 ball powder, the (CCI #450's) produced less velocity than the standard (CCI #400) primer, along with higher SD. Was it a significant difference? On paper, no... and I don't know about at the target, I didn't test these loads for accuracy, it was only to explore the differences in primers. But it did open my eyes up to the differences in primers, and their potential effects on my handloads... it's one of the reasons why I'll evaluate 2 different primers in my accuracy load workups, now.
My intent is to explore the best accuracy for the money. With that in mind I don’t know that I’ll buy the #34 primers anymore as they are more expensive if say WLR or CCI 200 primers are available. Availability is a pretty significant concern so I won’t say never so I’m also looking for some variety.
'best accuracy for the money' is a nebulous goal... but likely one most of us have to consider. For some people, it's 'best accuracy, money be darned', and for others it might be 'hit the bullseye for as cheap as possible.' It sounds like you are in the middle with me... that is, reasonable accuracy for reasonable money. The exception to that, these days anyway... is finding components for
any money.
Be aware, though, that if you work up with #34's, and then change to WLR's or #200's, for example, you will very likely have to reduce a bit and work back up to find your accuracy node, again... using more components. At the end of the day, however, the bullet does most of the work as far as accuracy is concerned... 'spend the money on the bullet' is one of my reloading axioms.... consistent, of course, with my budget and availability.
I did some 200 yard primer testing a while back, nothing too earth shattering except the 6.5 are not intended for my rifle.
