diyahbeetuz
12-10-2020, 06:55 PM
Hello folks and I hope y'all are having a good day. We all know that reloaders all over our great nation are hurting for components. Various pro-2A social media influencers are even forecasting an extended scarcity of ammo and reloading components that may last for years, which I dearly hope would not be the case. Some may have been lucky (or diligent enough) to get stocked up over the years, but newer reloaders (like myself) are unfortunately facing tough times.
I know it is generally taboo to discuss "unsupported" configurations of components, but I personally believe in ingenuity and resourcefulness especially during these times. IMO the key is to do it safely and within reason. With that said, I have to ask everyone's opinion on primer substitution, specifically the usage of small magnum pistol primers in cast 223 AR loads.
After doing some research I've found that there are basically two things that render this idea as a big No-No. Slam-fires due to thinner cups, and excessive case pressures that would damage the primer.
People online say that small magnum pistol primers have thicker cups than the regular SPP's, but not as thick as SRP's so there is high risk of slam fires especially when using rifles with mil-spec BCG's. To test this theory, I actually sacrificed a few Federal 200's and Remington 6 1/2's and primed 10 .223 cases each. I loaded 10 of each into two mags, inserted them into the magwell of my competition build AR with an "enhanced" firing pin, dropped the bolt on each primed case, then ejected them without squeezing the trigger. None of the primers popped at all. Then I did the same thing using my bone stock Ruger SR-556, still no popped primers. I will have to test and see if repeated strikes of the floating firing pin would cause an ignition on either rifles, but so far it hasn't done anything to the primers except to leave a slight indentation which is typical in AR platforms. The results of my experiment does not conclude that SMPP's and Rem 6 1/2's are completely safe to use in .223. it did however exhibit that using my current equipment and components, the probability of experiencing a slam fire is low although not impossible.
Typical 223 case pressures using J boolits reside in the 40-50K PSI range depending on the load data. However with .223 CB loads I'm seeing lower recommended powder charge weights resulting in pressures way less than those numbers, granted that those load data are probably for bolt-action platforms and not for semiautos which require a certain amount of gas volume to operate as designed. I understand that reliability in semiauto use is a separate issue, but assuming that I successfully develop a CB load that would cycle my semiauto reliably and produce acceptable accuracy without exceeding the maximum case pressures that small magnum pistol primers are designed for (possibly use an adjustable gas block, or a suppressor which would increase gas to the bolt, or even a lighter action spring), would there be any reason NOT to use small magnum pistol primers in 223 CB loads other than "it is not recommended"? Would the same be true with using Remington 6 1/2 SRP in 223 loads if case pressures are nowhere near jacketed boolit numbers?
This topic may be way over my head to completely understand, but any meaningful and sensible comments or advise is greatly appreciated. I do not mean to stir the pot and cause confusion or misinformation, I am simply trying to make do with what I have on hand to get by during these trying times. Stay safe y'all and God bless.
I know it is generally taboo to discuss "unsupported" configurations of components, but I personally believe in ingenuity and resourcefulness especially during these times. IMO the key is to do it safely and within reason. With that said, I have to ask everyone's opinion on primer substitution, specifically the usage of small magnum pistol primers in cast 223 AR loads.
After doing some research I've found that there are basically two things that render this idea as a big No-No. Slam-fires due to thinner cups, and excessive case pressures that would damage the primer.
People online say that small magnum pistol primers have thicker cups than the regular SPP's, but not as thick as SRP's so there is high risk of slam fires especially when using rifles with mil-spec BCG's. To test this theory, I actually sacrificed a few Federal 200's and Remington 6 1/2's and primed 10 .223 cases each. I loaded 10 of each into two mags, inserted them into the magwell of my competition build AR with an "enhanced" firing pin, dropped the bolt on each primed case, then ejected them without squeezing the trigger. None of the primers popped at all. Then I did the same thing using my bone stock Ruger SR-556, still no popped primers. I will have to test and see if repeated strikes of the floating firing pin would cause an ignition on either rifles, but so far it hasn't done anything to the primers except to leave a slight indentation which is typical in AR platforms. The results of my experiment does not conclude that SMPP's and Rem 6 1/2's are completely safe to use in .223. it did however exhibit that using my current equipment and components, the probability of experiencing a slam fire is low although not impossible.
Typical 223 case pressures using J boolits reside in the 40-50K PSI range depending on the load data. However with .223 CB loads I'm seeing lower recommended powder charge weights resulting in pressures way less than those numbers, granted that those load data are probably for bolt-action platforms and not for semiautos which require a certain amount of gas volume to operate as designed. I understand that reliability in semiauto use is a separate issue, but assuming that I successfully develop a CB load that would cycle my semiauto reliably and produce acceptable accuracy without exceeding the maximum case pressures that small magnum pistol primers are designed for (possibly use an adjustable gas block, or a suppressor which would increase gas to the bolt, or even a lighter action spring), would there be any reason NOT to use small magnum pistol primers in 223 CB loads other than "it is not recommended"? Would the same be true with using Remington 6 1/2 SRP in 223 loads if case pressures are nowhere near jacketed boolit numbers?
This topic may be way over my head to completely understand, but any meaningful and sensible comments or advise is greatly appreciated. I do not mean to stir the pot and cause confusion or misinformation, I am simply trying to make do with what I have on hand to get by during these trying times. Stay safe y'all and God bless.