Enfield revolver over pressure

[Baal]

I took my 1931 Enfield No2 Mk1 revolver to the range today. I had loaded 50 rounds with 200 grain cast lead bullets over 1.7 grains of Unique powder. That's the suggested starting load in my Lyman reloading manual for a 195 grain lead alloy bullet. And this site (http://www.handloads.com/loaddata/default.asp?Caliber=38%20SqqqW&Weight=All&type=Han dgun&Source=) suggests starting at 2.4 grains. So I figured 1.7 was light if anything.

As as it turns out, I only fired 6 of the 50 rounds. Nice tight group at 10 yards, fired single action, one handed.

Overpressure!

My first thought was the spring in the cylinder had broken when I broke the revolver open and the ejector didn't move. But nope, it's fine. I had to remove the cylinder and use a screwdriver to push the brass out. I'm guessing, 30 or 40 pounds pressure required to push the brass free. Examining it, the heads and primers show definite flattening and the brass wall is bulged.

As as soon as I get the chance I'll pull the other 44 bullets. I'm certain I used 1.7 grains as I only have a single stage press and always weigh out each individual charge. I'll confirm that though.

I have a full pound of Unique and maybe a half pound of Herco. And most of a pound of Trail Boss. I'm thinking 1.4 or 1.5 grains of Unique. But will have to see if I can find loads for those other 2 powders too.

Anybody have any pet loads they care to share?

Information

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[browningautorifle]

So very hard to say without having stood beside you when you were loading... Definitely it didn't like that load. Not as hot as B'seye...a bit smokey though. I went to the Alliant site and Unique didn't even list for 38 S&W... That says bags to me if they don't list it at all. 1.7 should have been light but perhaps too light, the air space made it even an greater pressure.
Alliant Powder - Reloader's Guide

[mr.e moose]

I think you may be heavy on the charge with a 200 grain bullet, I don't have my reloading data handy but I will try to get back to you tomorrow. Did you mic your bullet to see what diameter it is? Some molds will throw a bullet 2 or 3 thousands over and if you are using a hard cast bullet it will increase pressures. Also a low load will increase chamber pressure because of a increase of air space.

[Baal]

I'm using a 200 grain pure lead bullet. 0.362" diameter.
I haven't slugged this revolver's barrel, but I suppose I should do so though.

[CINDERS]

If you have to much air space your going to have to use a filler to keep the powder against the primer, I suffered over pressure in my 6.5x284 trying low density loads for less pressure high velocity (Using a faster powder) had a primer fall out after firing 2 rounds so stopped. I surmised that with the increased air space suffering more of a detonation as the flash ran across the top of the powder I now ensure load density is at 90-95%.
The load I was trying to develop was with WIN 760 ball powder and going from my Quickload program with the powder variation set at 5% it showed good pressure from memory around the 48-49000 psi for about 2850-2900fps with a 140gn VLD using a 215M primer as the load density was around the 70-75% I think, out of a 30" barrel so I did not just say in my head this equals that and alls well in the world.

It is never really a good idea to go below minimum loads even with years of experience and constructing the load in your head by saying this equals that..... as manuals state going under minimum load data it can be a dangerous undertaking.

Slug the bore and see what it mikes to V's your cast measurement I do not see the extra 5 grains of weight as a factor to drop below the recommended lowest load

[RCS]

I have two Uberti revolvers, the 1851 and 1861 models, both converted by me to use the 38 S&W cartridge. Modern steel cylinders and recoil plates were used. The bores are .375 inch and I use a 127 to 130 grain hollow base lead bullets around 359 diameter with 2.7 grains of Unique. These are not target pistols but have a certain amount of accuracy at
close ranges. Empty cases eject without any problems and without sight of high pressure and they are fun to shootAttachment 84201Attachment 84202

[browningautorifle]

200 grain pure lead bullet

That one should be soft enough too... I'd still change powder and use a factory recommended charge.

[old tanker]

I have been using 2.0 grains of Bullseye with a 200 grain bullet cast from an NEI #169a mould. No problems in my Enfield No.2 Mk I* revolver, the Lend-Lease S&W British Service Revolver or in a Colt Police Positive. I would not use that load in any of the old break top revolvers like the S&W New Departure, H&R, Iver Johnson et al.

[25-5]

I use 200gr .361 lead bullets from Matt's Bullets. They do measure .361. I started at 2.3gr of W231 which is a published load. I also worked up a load with Titegroup, but that is not published. I have had no problem signs and have shot a lot with great accuracy. I measure each load as well and there is little or no air space.

[Baal]

The local Wholesale Sports has W231 in stock and on sale. I'll pick up a pound tomorrow.