38SPL case length


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fourdollarbill
March 6, 2010, 02:34 PM
I'm loading some 38spl +P 125gr XTP's so the perfect crimp is in order. I never trimmed 38spl brass before or had a reason like the 357 mags. Am I wrong??? 38spl is 1.155" and trimmed to 1.149" right? Well today I found near all my brass from various boxes way off the mark. New Starlines are 1.148", the 5x fired RP's, Fed's, Frontiers, etc... are all 1.140" to 1.147". I sampled all three boxes of 1k and the same measurements with the high majority to 1.140" size. All of the nickel are the same.

Ultimately I just trimmed these 20 down to 1.140" to assure the crimp was good. Similar to 357mag I don't think it will be a major pressure problem but what gives? Normal?

While I'm thinking about it... Will XTP's actually work @ 900 fps? I'm going to shoot into water filled barrels today to find out.

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rcmodel
March 6, 2010, 03:03 PM
Hornady #4 rates the 125 grain XTP usable velocity range as 850 - 1,600 FPS.

OAL is always measured & trim done after sizing, but before neck expanding.

Max case length is 1.155"
Trim to length is 1.145"

rc

ReloaderFred
March 6, 2010, 03:26 PM
Since the .38 Special headspaces off the case rim, you can actually trim to any length that works. It's an old blackpowder cartridge, and there's plenty of room in the case. If you shorten them by a considerable amount, say .125" or more, it would reduce the case volume and you'd have to work up your load accordingly, but a few thousandths isn't going to amount to a hill of beans difference one way or the other.

Hope this helps.

Fred

Walkalong
March 6, 2010, 04:15 PM
Since the .38 Special headspaces off the case rim, you can actually trim to any length that works.and since I had quite under 1.145, so I trim all my .38 Spl cases to 1.140. Nice consistent crimps. Some people don't trim them, and it will work pretty well, but I am anal about crimps, so I trim them.

I know a fellow here who cleans all his pistol primer pockets, but doesn't trim the brass (Well, he does have a metric butt load to do).

I trim all my revolver brass (Much less than a metric butt load), but don't clean pistol primer pockets.

SlamFire1
March 6, 2010, 05:06 PM
I have never trimmed a 38 Spl case and probably never will.

I can't tell you the tens of thousands of 38 Spls I have fired.

I tumble them, then run them through my Dillion 550B.

I shoot them in a variety of 38 Specials.

jbrown13
March 6, 2010, 05:18 PM
Hornady #4 rates the 125 grain XTP usable velocity range as 850 - 1,600 FPS.

OAL is always measured & trim done after sizing, but before neck expanding.

Max case length is 1.155"
Trim to length is 1.145"

rc
And, I seem to remember seeing somewhere that 1.135" is minimum case length for 38 special, but I have been wrong before.

fourdollarbill
March 6, 2010, 06:05 PM
OAL is always measured & trim done after sizing, but before neck expanding.
Yes I do, forgot to mention it...
True, brass will grow about .005 after sizing.
I had always sized and then expanded without the belling. It fits my trimpro pilot better. It measures the same after expanding (without the bell).

Well, I just shot those 125gr XTP's at about 900 fps and they sure did open up in the water. Good to know...

joneb
March 7, 2010, 01:13 AM
With the .38 spl brass I reload I have found case length variations from 1.142 to 1.155" so I trim my brass to 1.145-1.147".
Those that do not trim their revolver brass either have more consistent brass than I have, or they don't crimp much.

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