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Max Pressure The Receiver Can Handle?


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#1 JimFromFL

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Posted 22 January 2004 - 05:16 PM

Reading the specs on some powders it is strange but some powders that produce mild recoil actually produce higher pressures than other rounds.

I like the Clays powder as it produces a nice slow velocity which makes for extremely mild recoil, BUT it produces higher pressure than other powders with a hotter load?

When reloading what would be the max pressure to avoid. This will help in choosing a powder and if I should stick with the Clays.

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#2 Grey Crow

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Posted 23 January 2004 - 01:48 PM

I would tend to lean towards the basics of reloading, with a wary eye on the spent cartridge. Start low and slowly increase amounts of powder, watching for the effects on the case, blown primers, split cases, deformation of the headstamp. All signs that you are nearing maximum pressures for the primer, powder, bullet combination.


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#3 JimFromFL

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Posted 24 January 2004 - 09:36 PM

Wow.... Thanks for the education.

It got me thinking.....

Didn't they post pressure limits for the barrel?
I thought the British used a stamp on the barrel if a specific pressue.

Anyone know what this pressure would be???? dry.gif
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#4 PK.

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Posted 24 January 2004 - 10:07 PM

The Brits proof everything that comes into there country, even if it was done at manufacture.

SAAMI specs for 45 acp

19,900 CUP Max Product aver. for factory loaded ammo

28,500 CUP nominal proof pressure.

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#5 JimFromFL

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Posted 24 January 2004 - 10:40 PM

PK,

Thanks for the update.
If the barrel is approved for 19,900 CUP Max Product aver. for factory loaded ammo, is it safe to "assume" the receiver is at least that same?

Currently Clays is said to produce 17,000 CUP with 4.0 gr of powder @ 1.200 AOL.
My current loads are with 3.7gr @ 1.255 AOL which I figure is below the 17,000 CUP.

Am I on the mark? wink.gif
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#6 Grey Crow

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Posted 25 January 2004 - 07:59 AM

Thanks Phil,

I to date use 231, Red Dot, and Unique for handgun loads, following the recipes in the manuals. I seem to reach accurate loads before reaching the maximum.
To me loading for accuracy is far more important than seeing how fast I can push a bullet down range.
Loading for the Thompson is far to expensive considering the cost of case lots of commercial loads.
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#7 Grey Crow

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Posted 25 January 2004 - 05:14 PM

I must agree Phil, commercial loads aren't perfect! I'm certain that the degree of care is far from what "we" might exercise while loading.

Function and accuracy, are important without tearing the gun apart with hot loads.

I've owned several handguns that consumed nothing but hand loads without incident or misfire.

I own a modern 27 It would take a very long time for me to be able to afford to replace it, I still treat it with the same respect that I would a 28 or earlier, Perhaps one day I'll have the good fortune of adding a classic to my selection of arms.
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#8 JimFromFL

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Posted 25 January 2004 - 10:35 PM

One point that I may not have stressed is the fact that I am following the Hodgdon's Book for the Clays powder and am about .1 or. 2 below the max load and seating the bullet about .05 longer than it should. According to the manual the max pressure is 17,000 CUP (only the max pressure is listed) so I should be just a bit less than that.

I noticed that other powders in the Hodgdon's book list max pressure of 100 to about 2,000 less CUP which is what really got me wondering about pressure.

I did some research on powders other than Hodgdon and found some interesting info.

231 ranges from 14,900 - 19,200 CUP
WST ranges from 15,500 - 19,900 CUP
Red Dot max is 16,200 CUP
Unique max is 16,000 CUP

So, although other powders seem to be about the same (17,000 CUP) or more it appears the 17,000 CUP may not be as much as I originally thought.

Please concur if this seems about right and sticking with this powder (which produces great accuracy and mild recoil) should be fine.
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#9 PK.

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Posted 26 January 2004 - 08:52 AM

Jim,

There is a lot to consider about actual pressures generated by particular ammo in a particular gun; much to deep right now.

I can say with a great comfort; if you stick with all aspects of the published data for 45 acp (which apparently you have), you will be just fine. I can not see how Clays, in and of itself, could be a problem.

Load ‘um & shoot!

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#10 xausa

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Posted 26 January 2004 - 04:01 PM

Thompsons can absorb a lot of punishment, as I found out in Vietnam 39 years ago, when my mismatched ex-ARVN M1A1 had a case separation, leaving the front part of the case in the chamber, effectively preventing the next round from chambering, but not from firing.

Fortunately, I am right handed, and after spewing bits of case out the ejection port until I could stop firing and extract the separated case, the gun kept on cooking.

Also fortunately, this did not occur in a combat situation, but if it had, wouldn't I have been better off with the M1A1 than with an M1, which wouldn't have fired with an open bolt?

Food for thought.

(I replaced the A1 bolt with an M1, which Numrich thoughtfully shipped to my FPO address.)

Bill
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