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View Full Version : Rifle primer in pistol bottle neck case???



abunaitoo
03-09-2011, 05:44 AM
I found a load for an 8mm Nambu.
It said you should always use small rifle primers in any bottle neck pistol case.
I've never heard this befor.
I've always used small pistol primers.
Anyone know anything about this????

Linstrum
03-09-2011, 06:14 AM
What do your reloading manuals say? I don't have any that cover the Nambu, so I can't look it up.

The use of pistol primers versus rifle primers has more to do with the depth of the primer pocket, pressure the cartridge operates at, and the amount of powder the primer has to ignite. Rifle primers are slightly taller than pistol primers and require a deeper pocket. Also, rifle primers are thicker because rifles tend to run at much higher pressures than pistols and protection from blowing out is needed. Note, I said tend to run at higher pressures, some pistols like the 9mm Parabellum and the newer magnum pistols run at rifle pressures in the range of 35,000 to 50,000 cup and above, depending on load and projectile weight. However, the amounts of powder in pistols tend to be much less than in rifles. Another factor is that pistol firing pins sometimes don't strike as hard and when rifle primers are used (if they indeed will fit the brass without protruding from the pocket a few thousandths of an inch) the pistol's firing mechanism may be too weak to fire the cartridge reliably.

So, pistol primers are slightly shorter, they are made from thinner sheet stock, and they do not produce as much fire.

Other than what I just mentioned I don't know how to draw a clear distinction between when to use pistol primers and rifle primers. I use pistol primers in my 9mm Parabellums and rifle primers in my .30 carbine. Measure your Nambu pistol brass primer pocket and see how deep it is, and use the primer that will fit. I have used small rifle primers in pistols without any problem, at least when they fit and didn't protrude.

I'm sure others will have some ideas that relate to the question that I didn't mention.


rl991

bobthenailer
03-09-2011, 07:54 AM
It is possible to interchange small pistol & small rifle primers ! just work up the load with the selected primer .
I as well as many other shooters used SRP in the 38 super for ipsc. / action pistol . I have also used sp primers in the 454 casull that calls for sr primers with tightgroup powder for loads to 1200 fps.
Also some people have gotten better accuracy from the 22 hornet useing SP instead of SR .
However the large pistol and large rifle primers are not interchanable as the primer cup has different demnsions.

cajun shooter
03-09-2011, 11:12 AM
Bob, The LR andLP have been interchanged many times, sometimes with good and sometimes with bad results. The 45-70 cartridge is one that I have done this with by using the LP rather than the LR. I have taken the two in Federal and the LR was .125 in height and the LP was .120 giving a difference of .005 which would only cause problems if one was using brass with very shallow primer pockets. This would cause the anvil to crush a little while setting. I don't ever recall a problem with that. The biggest one is the hardness of the outter cup and the firing pin spring strength. A heavy modified gun might have problems with misfires and if firing high pressue loads the hotter primer would increase pressure. I am not saying to do this practice as I myself use the proper primer for the job. It can be done is my point and with the 45-70 it gives very good returns. I also realize that the OP was talking about BN cases. My answer was to you on your last sentence.