Author Topic: Bring back an oldie: The 38/45acp but magnumized  (Read 180 times)

ss30378

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Bring back an oldie: The 38/45acp but magnumized
« on: November 20, 2017, 11:24:59 AM »
I'll start with I had an extra 6" g20 9mm sitting around with no purpose as well as a bunch of SPP 45 acp brass.  I got to thinking...  I remembered the articles back in the late 90s about the 38 casull and the speeds they were getting which were impressive at the time (124gr at 1800 with h110).  I figured I could possibly make this a reality so I contacted my friend who does some smith work and he believed it could be done.  The goal was to recut the 9mm chamber to a 38/45 add a comp and run it in my g21 longlslide.  This will be loaded to 38 casull specs, not the old 38/45 specs.     

I looked on ebay and found a like new 38/45acp die set for sale that I won for about half price over a new set from rcbs.  Then after I received the dies I "tried" forming acp brass in a single stage but that was a bit far fetched.  The forming die from rcbs was also a pricey piece but looking at pics the form die resulted in something very close to the 400 corbon.  So i grabbed a lee 400 corbon dies set for $30 and bingo I have the right combo for good looking brass!

I made a few dummies up with the heaviest bullet I planned on using and sent the barrel and slide assembly off to get chambered.  Comparing the case capacity to the 9x25 Dillon the 38/45 case held about 1.5g more of 300mp when filled to the top.  Should make for some good numbers and that big sharp shoulder should help with getting the slow powders burning (Its like a WSM pistol round).  The barrel has been chambered and has great case support right up to the extractor groove.

So far the preliminary tests have resulted in a 125gr xtp (.357 dia) over 20.5gr of h110 averaged 1876fps and 977lbs of energy.  WIN standard LP brass and WIN LP primers were used for this load.  The standard LP primers were starting to flatten at this level but case heads were still down at .479".  This gun will be running a compensator on it shortly and should be very effective at taming the beast since.

My ultimate thought with this project was to have something "unique" that had cheap plentiful brass with 357mag ballistics but was soft shooting.  The goal wasn't really to be a light bullet at rifle velocity setup but it looks like it may be great as a coyote pistol!  I'll work up to 180gr pills over slow powders and see what it can do.

Not too bad for an old wildcat!

ss30378

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Re: Bring back an oldie: The 38/45acp but magnumized
« Reply #1 on: November 20, 2017, 02:35:35 PM »


Yes I call it the 38wby as it reminds me of the weatherby rounds.
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« Last Edit: November 21, 2017, 07:44:20 AM by ss30378 »

my_old_glock

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Re: Bring back an oldie: The 38/45acp but magnumized
« Reply #2 on: November 28, 2017, 06:38:43 PM »


I had drawn up some plans for a 9/45 (45ACP necked down to 9mm). Basically, the same thing. I didn't have access to a machine shop, so it never got past the drawing stage. 

Trapper6L

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Re: Bring back an oldie: The 38/45acp but magnumized
« Reply #3 on: November 28, 2017, 08:51:30 PM »
I built a 38/45acp back in the 80's using a 38 Super barrel. I used a Gov't model 1911 Colt. Did all of the Gold Cup mods to it. It shot pretty good with groups at 25yds from bags at an inch with 125gr HPs. All it turned out to be was a 357 semi auto. I had tons of issues with cases that would split during the forming process. And that was using annealed brass. Brass life in mine was a paltry 3 times thru the gun and it was done. Split necks were common. I still have it but it's probably been 20 years since I've seen it. I guess I should dig it out of the vault one of these days. Then there's finding the ammo and all things considered, that's probably why I won't be shooting it any time soon. Far too many that I load for and far too much of too little sitting in the cabinets and boxes.

ss30378

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Re: Bring back an oldie: The 38/45acp but magnumized
« Reply #4 on: November 29, 2017, 07:46:10 PM »
I’ll consider my self fortunate then!  I just made up about 500 pieces of brass and only messed up 2 so a .4% failure rate is pretty good in my mind.

I’ll start working up more data in the next few weeks but I believe 2000fps with a 125gr is attainable with what I’ve seen so far in my gun.  I’m more interested in the heavier bullets but it’s always fun seeing the chrono edge closer to that 2000fps number.


Captain O

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Re: Bring back an oldie: The 38/45acp but magnumized
« Reply #5 on: December 12, 2017, 12:00:24 PM »
The original .38/.45 Clerk (pronounced Clark) was a fairly good performer. a modern, "Magnum" level version should prove interesting.
Captain O

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This post is approved by Arf, The Wonder Chicken.