Open Gun Primer Choice

[Jeff686]

My current load:

38 supercomp (starline)

7.4 of 7625

winchester small pistol primers (WSP)

170pf with 8ports + comp

Primers look fine, no signs of excessive over pressure.

In the past, when loading 38 short colt, WSP looked fine, Fed looked flatter. I assumed that this was because the Fed were softer. Changing primers from WSP to Fed should not have drastically increased pressures.

So, I need primers! I'm running out of WSP. I found some Federal Match SP primers. I'm thinking about using them for my open gun. If I see signs of pressure with Fed primers and the same load as WSP (flattening, but not cratering), should I worry?

Any reason not to use the Fed primers in my open gun? Any possible problems?

My alternative is to borrow a box of WSP from a generous friend, but I hate to take advantage of him and worry that he might run out. I have an order in at Grafs for 5k for myself since May, and I'm hearing rumors that backorders from April are starting to show up.

Going to the Nationals in Sept, so I need to feel good about my ammo.

[uscbigdawg]

Jeff - Nothing wrong with running pistol primers in major PF loads. You're not pushing them hard at 170PF.

Rich

[JThompson]

At this point, whatever I can find that goes bang.

[CocoBolo]

I do not use Federal in my open gun because they are just too soft. If your going magnum match you probably can drop a tenth or two off the powder as the primer will probably bump 10 fps or more. I run CCI small pistol. Lots of guys shoot small rifle, all they are doing is masking the high pressure signs. I can tell their brass when I run it thru my CasePro it takes a lot of pressue to roll them back down to size.

I shot IMR7625 for a while at 7.3 gr, good stuff, at night if you shoot 5 or 6 rounds then it will launch a big flame then normal for 5 or 6 an another big flame.

Edited June 5, 2009 by CocoBolo

[jmorris]

I use WSR

[HSMITH]

If you need something more than Federal small pistol or small pistol match primers to conceal the pressure signs you are on the wrong track, your load is over pressure and you need to address IT and not the primer choice. I run 9mm major at 176-180 PF and have no flattening of Federal small pistol primers with several different powders, my main match load is 3n-37 at 176 power factor with 115 grain bullets and the primers are not flattened at all. I load all my 'important' match loads with Federal small pistol primers in case there is one that isn't seated well, the Federal primers are a lot more tolerant of being not quite seated all the way than any other primer and gives me a small margin of error insurance for my ammo.

[jmorris]

Funny, I always used rifle primers for the "small margin of error insurance" reason (just in a different area). Good thoughts though.

My reasoning comes from the fact that I don’t have access to the equipment to measure actual pressures of the loads I use; however, none of the loads here would make 165pf http://en.wikipedia.org/wiki/9x19mm_Parabellum and several are quite a bit passed not only SAAMI’s 35,000psi pressure limit for 9X19 but also the 38,500psi +P pressure limit. Even the +P+ (all that means is that it’s over 38,500psi but who knows by how much) don’t make it. We need someone with equipment to do some tests.

[smokshwn]

Funny, I always used rifle primers for the "small margin of error insurance" reason (just in a different area). Good thoughts though.

Its a common misconception that you "need" rifle primers for what you referenced as insurance, however they actually narrow the margins due to the fact that some pressure signs are hidden. It never made sense to me that solutions for primer flow (rifle primers, and longer firing pins) simply hide the fact that there is too much pressure in the load.

[Hatchet Jack]

If you need something more than Federal small pistol or small pistol match primers to conceal the pressure signs you are on the wrong track, your load is over pressure and you need to address IT and not the primer choice. I run 9mm major at 176-180 PF and have no flattening of Federal small pistol primers with several different powders, my main match load is 3n-37 at 176 power factor with 115 grain bullets and the primers are not flattened at all. I load all my 'important' match loads with Federal small pistol primers in case there is one that isn't seated well, the Federal primers are a lot more tolerant of being not quite seated all the way than any other primer and gives me a small margin of error insurance for my ammo.

Mr. Smith - Care to share how much 3N37 you use with the 115s? Also the COL? I've heard that 3N37 advances bore erosion - have you seen this to be the case?

Thanks in advance.

[HSMITH]

Hi Jack, I am loading at 1.18" and using over 8 grains. My barrel is specifically set up for long loads, and specifically set up to lower pressures. If your 9mm gun has a typical 9mm major chamber my load won't work. I think you really need to start well under 8 grains and work up, chrono map the loads so that you know what is going on and I would do the load development with Federal small pistol primers.

I have 30K + of the 3n-37 loads through the gun and over 50K total, it still shoots under 3" at 50 yards with me shooting it and I have seen no real decline in accuracy since the gun was new, so I would say that the bore erosion concern has not been an issue for me at all. 3n-37 puts a wicked amount of heat into the gun and it does it VERY quickly, if you were to get aggressive in practice and shoot a lot in a short amount of time I could see the barrel getting torn up in just a few thousand rounds. If I am shooting the gun and it gets hot I cool it down before shooting more and that has possibly saved my barrel. I put the gun in a bucket of water or pour water on it or spray brake cleaner through the bore to cool it, not exactly the best treatment but I believe it to be a lot more friendly to the barrel than getting it too hot. My barrel still shoots really well.