45 acp -- minimum oal


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nulfisin
January 7, 2010, 12:06 PM
The guides all publish maximum OALs. I've found, though, that what actually fits in the barrel is almost always far shorter. For example, I recently loaded some 230 LRN (plated) over 4.6 grains of HP-38. The published OAL is 1.200, but most of my rounds needed to go down to about 1.15, or even slightly shorter. Is this normal? I'm worried about creating too much pressure. Thanks.

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Walkalong
January 7, 2010, 12:21 PM
Not too big a deal with the big case and low pressures of the .45. Find an O.A.L. that feeds well in your gun and work up a load using that O.A.L. If it is considerably shorter that the O.A.L. the manual used, stop short of max data a little bit. Besides, 4.6 Grs of HP-38/W-231 and a plated 230 Gr RN is a light load.

1.200 is very short for a 230 Gr bullet, but if that is what your gun needs, so be it. I load them at 1.260.

rcmodel
January 7, 2010, 02:03 PM
Mil-spec for a FMJ-RN 230 hardball load is 1.266" - 1.271".

If you load some other bullet shape with a full diameter shank running further foreword, (Like a SWC, JHP, or TC) you will have to seat shorter to keep from hitting the leade.

1911 Match barrels are often short throated for best accuracy with FMJ-RN, and some foreign designed guns have short leades intended for FMJ-RN military ammo.

rc

nulfisin
January 8, 2010, 09:52 AM
The SAAMI diagram seems to say that 1.190 is the minimum OAL. I'm not sure how those diagrams are created and what load data they rely on. How important are the diagrams? Thanks.

Walkalong
January 8, 2010, 10:45 AM
SAMMI gives a min and a max for the caliber. Good guidelines for the novice, but otherwise almost meaningless.

Your mags will tell you the max they can be, as well as the throats in your guns. Common sense and whether they will feed will give you the minimums.

Load the bullet to a reasonable O.A.L. that feeds 100% in your guns and work up your load.

stork
January 8, 2010, 11:48 AM
A general rule of thumb for SWC bullets, is to leave 1-2 thickness' of bullet lead (the shoulder, not the sloping portion) exposed above the mouth of the case. Then taper crimp to .463-.470. For round nose bullets, set your seating die to match factory hard ball dimensions.

Testing your gun will tell you if your barrel likes a tight crimp or a light crimp. The first Kart barrel I had installed loved a tight crimp (.463-.465). The second seems to prefer a lighter crimp (.469).

Stork

mineralman55
January 22, 2010, 08:29 AM
"A general rule of thumb for SWC bullets, is to leave 1-2 thickness' of bullet lead (the shoulder, not the sloping portion) exposed above the mouth of the case."

1-2 what? Thousandths of an inch?

Larry
Louisiana

stork
January 22, 2010, 10:44 AM
Geeese, I need to have a few more cups of coffee before my fingers engage the keyboard.

What I should have posted is: Leave 1 or 2 thicknesses (of a fingernail) of lead exposed above the mouth of the case.

It's a general rule of thumb that was passed onto me 8 or 9 years ago and I've followed it for over 38,000 rounds out of my match guns and carry guns. I've never had a problem that could have been attributed to OAL.

I know there are exact measurements to address OAL. However, with the wide variety of bullet nose shapes, various bullet weights with the same nose shape available not to mention variations in bullets themselves, this rule of thumb has worked with every style of SWC bullet I've loaded.

Remember, the 45 ACP isn't a bench gun (I shoot those also). The bullets do not have to be loaded to touch the lands, they have to be loaded to function every time. Your natural area of movement so far exceeds any possible advantage to loading long (and the resulting feeding problems) that it's just not worth playing with it. Just an FYI, my long line loads (50 yds) will hold under 2" with Ransom testing. I can't hold anywhere near that. A good day is 4", a normal day is 5-6".

FWIW

mineralman55
January 22, 2010, 11:20 AM
Thanks. That's a good rule-of-thumb. I'll have to get my caliper out to measure my fingernail thickness.:)

I spoke with Rudy at Billy Bullets because I'm about to load up their 200 gr. LSWC molys. He said load it so that the top band above the lube ring is about half exposed. I'll mike that as well, and let folks here know how it works out.

Canuck-IL
January 22, 2010, 12:36 PM
1-2 what? Thousandths of an inch?
Just use .928 - .930 case base to bullet shoulder ... you'll arrive at about the same place as the fingernail and other gauges.
/B

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