Primer issue in hot 357 loads

tactical870

tactical870

CGN Ultra frequent flyer
Rating - 100%
136   0   0
Location
Buckhorn, Ontario
Last night I was shooting some 357's loaded up with 12 gr of 2400, a federal 100 small pistol primer and 158gr hornady XTP hollowpoints. I was shooting them from a S&W model 27. According to my books 12 gr is a starting load yet all primers were flattened and I was getting quite a bit of blowback. I suspect the primers are way too soft and that is my issue. Anyone have any experience with this? Thanks
 
You are using the incorrect primer. Fourth Edition Hornady handbook (pg 565)calls for the use of Federal 200 primers with your loading. Fed 200's are small pistol Magnum primers.

http://www.federalpremium.com/ammunition_catalog/primers.aspx

100 Small Pistol Std. velocity pistol and revolver .175
150 Large Pistol Std. and magnum pistol and revolver .210
155 Large Magnum Pistol Magnum revolver .210
200 Small Magnum Pistol High velocity and magnum pistol and revolver .175
205 Small Rifle Small rifle .175
210 Large Rifle Large rifle .210
215 Large Magnum Rifle Magnum rifle .210
 
What do you mean by "getting quite a bit of blowback"?

Blowback usually refers to gas escaping rearward and cutting the breechface, but you said your primers were flattened, not pierced or ruptured...

I almost always get flat primers shooting .357Mag, whether or not I use mag primers. Unless you're rupturing primers, you most certainly can "get away with" using regular primers.
 
I have never had issues changing between mag and re small pistol primers. With the reg your pressure should actually be slightly less.

Flat primers are not the end of the world. If you are using published data u should be fine. Try loading down a bit. You might find flat primers dont go away until you get really low.

Is the forcing cone and barrel leaded? Is the timing off on the gun raising pressure? The blowback concerns me more than the primers.
 
Are your cases blackened at the neck?, do you have much unburned powder left in the bore?.

2400 is pretty slow stuff, seems to need some pressure to move into it's best burning zone.
Another grain or two may solve that blowback problem.

As to primers, should not be a big deal at .357 MAP of 35,000 psi.. Always used magnums in case it got really cold.

Haven't capped a .357 in many moons, but the old load notes say max. 14/2400/158swc., in a K frame model 19. (damn, I miss that smith)

internet advise .... YMMV.
 
Does your revolver have any endshake ie does the cylinder have any movement front to back you can feel? a loose cylinder will cause the primer to back out a little at ignition and then recoil will push the casing back and the primer will look really flat. But Federal primers are soft and tend to flow out to the edges of the primer pocket anyway. As long as you are not getting cratering or pierced primers and the cases extract easily enough I imagine you are good to go.

Maybe post a picture if you can
 
ampegor said:
But Federal primers are soft and tend to flow out to the edges of the primer pocket anyway. As long as you are not getting cratering or pierced primers and the cases extract easily enough I imagine you are good to go.
Click to expand...
My thoughts exactly. Federal magnum primers will be just as flat as regular Fed primers.

Suggesting mag primers must absolutely be used in any cartridge that has the word "Magnum" in it is simply bad advice.
 
I don't believe the cups of Magnum vs Regular primers of the same brand will be any stronger.
 
Any standard primer should be fine. As stated, I don't think there is any difference in the cup, between standard and magnum.
12 grains of 240 is a fairly heavy load. That got me close to 1300 in a 27 and 13 grains gave me 1335. My primers were pretty flat, with tight fitting cylinder, but nothing to be concerned with.
I wish you would tell us what you mean by blowback.
 
I concur that Federal primers tend to flatten easily. In my experience, even light .38 Special loads will result in moderate flattening with them. Flat primers are not always a sign of excessive pressure in and of themselves; this is likely not a problem unless you are seeing other pressure signs.

If by blowback you mean the outsides of the cases are sooty, this is fairly normal with straight-walled cases.
 
Since "blowback" is a term used to describe a particular type of repeater action, I am curious just what phenomenon you are experiencing.
 
I use small rifle primers in my Marlin 94c in .357. 13gr of Bluedot on a 180 hp was rupturing small pistol primers. The cup is thicker copper for the rifle primer.
 
H4831 said:
Any standard primer should be fine. As stated, I don't think there is any difference in the cup, between standard and magnum.
12 grains of 240 is a fairly heavy load. That got me close to 1300 in a 27 and 13 grains gave me 1335. My primers were pretty flat, with tight fitting cylinder, but nothing to be concerned with.
I wish you would tell us what you mean by blowback.
Click to expand...



The cylinder spins freely. There are no issues there. By blowback, I mean that each time I fire a round I am hit by unburnt powder/debris. The gun is mechanically perfect, timing is dead on and lock-up is super tight with no excessive cylinder gap. It works perfectly with all my other loads and factory stuff.
 
I have experienced a similar problem. To solve it I lighten my load and that reduced the blowback. It could be the type of powder you're using. You might want to look into this.
 
tactical870 said:
Last night I was shooting some 357's loaded up with 12 gr of 2400, a federal 100 small pistol primer and 158gr hornady XTP hollowpoints. I was shooting them from a S&W model 27. According to my books 12 gr is a starting load yet all primers were flattened and I was getting quite a bit of blowback. I suspect the primers are way too soft and that is my issue. Anyone have any experience with this? Thanks

By blowback, I mean that each time I fire a round I am hit by unburnt powder/debris.
Click to expand...

12 grains 2400 is a mild load. My loads are 14.0 grains 2400 under 158 grain Speer JHP sparked by Winchester Regular Small Pistol.

BTW, this load is still .5 grains shy of full load. Some shooters over at the THR forum load 15 grains 2400 under 158 grain JHPs, which they say is for Ruger-use only.

Yes the primers are flattened with my 14 grain 2400 load, like all full or close to full load .357 mag primers are flattened. IMO, unless your Federal 100s flow in to the firing pin hole or are pierced, you should be fine.

Pictures will help show us what your flattened primers really look like, taken from a few different angles.

If you are getting unburned powder debris, maybe the primer is not hot enough to ignite powder 100% or your load is too weak...as mentioned above, 12 grains 2400 is weak. Try loading 13.5 to 14 grains 2400, or try another brand of primer. I do get a little unburned powder at 14 grains. BTW, unburned powder grains is more noticeable with BLUEDOT powder, even with full loads.
 
You must log in or register to reply here.
Back
Top Bottom