pressure 45 Colt

Maybe I missed this But here I go What would the pressure be for a 255 Keith SWC out of a Colt SAA with a load of 9 Grains of Unique ? I keep reading it is way to much .I have used this as a hunting load 30 plus years with the same gun . Just wondering.

I thank you in advance

The only pressure is living another 30 years to shoot that same fine load in your Colt, it's sure not a pressure problem from the gun unless it would be a 1st generation gun & if it was you wouldn't still have it.

Dick

Hornady 7th edition says 7.0 grains of unique is max with a 255 grain bullet for SAA and clones..... but it's a different style of bullet, so seating depth and resulting case volume will influence pressure. That said, 9 grains is quite a bit. If you want more oomph, Universal will give you a bit more velocity than Unique with a max load, according to the manual.

It is a Ruger load. You have used it with no problems in the past, so carry on!
gramps

RCBS cast bullet load manual shows 9.1 gr. of Unique to be a starting load for Ruger and Contender handguns. The show no lighter loads for Colt's and their clones for a Keith bullet. FWIW, the max for the Rugers/Contenders was 10.1 gr. I've been running 11.0 gr. with the RCBS version of the Keith bullet and it's noticeable.

The latest Lyman manual shows 7.0 gr. Unique for 827 FPS and 13,600PSI for pressure. The highest pressure they show for any load is 13.900 PSI.

I have a couple of Colts and the cylinder walls of the first generation gun are as thin as paper. The walls of the third generation guns are a bit thicker but I'd be leery of running a top load in those as well.

Paul B.

Here is an article by Brian Pearce that will give you a 'rough' idea of pressures. Rough because its data for a heavier bullet, but I use the same data for my slightly lighter 250g RNFP and 255g SWCs: https://www.riflemagazine.com/magazine/PDF/HL%20246partial.pdf . I've used 8.5g as my max, but I've seen others use 9.0g .

Thank you all This is a 2nd gen Colt still tight with no sign of wear .I have replaced the cylinder pin once in 30 years . I know 14,000 is SAAMI max but that is an arbitrary number and is for the 1st gen iron guns. Lawyers seem to be running these numbers. IMHO

best wishes

sixshot said:

The only pressure is living another 30 years to shoot that same fine load in your Colt, it's sure not a pressure problem from the gun unless it would be a 1st generation gun & if it was you wouldn't still have it.

Dick

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Well said, thank you This load has worked very well for me, nine Black bear and 15 Whitetails along with a few Coywolves .

30 years of use, no problems, carry on ! ps

We hear how weak the Colt SAA is and I wonder who started this ? I know SAAMI did their testing on an OLD iron framed Colt and came up with 14,000 and I suspect the legal beagles had a lot to say about that. Today's modern steel guns are a lot stronger and 14,000 is ridiculous. yet many spout that number these same individuals talk up the strength of Rugers and even endorse loads way above SAAMI .
I have seen Colts with cylinder bolt notches worn through and still function fine .
Strange world we live in. IMHO

I am not suggesting that you should throw caution to the wind These are my observations and my opinions .

I have one Colt single action .45 that was lettered to 1908. The cylinder walls are about as thin as paper when compared to the cylinder walls on the three third generation Colt 45's I have. Compared to the .45s, the walls on my .44 Spl. Colt SAA seem massive. I'm careful about what I run through those .45s as replacement costs are a tad pricey.
Paul B.

Your 1908 is not the modern Colt I am talking about I have several 1st gen Colts and I load at 14,000

Paul B said:

I have one Colt single action .45 that was lettered to 1908. The cylinder walls are about as thin as paper when compared to the cylinder walls on the three third generation Colt 45's I have. Compared to the .45s, the walls on my .44 Spl. Colt SAA seem massive. I'm careful about what I run through those .45s as replacement costs are a tad pricey.
Paul B.

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And you are told to load the 3rd gens to 14,000 also. Makes little sense except to the lawyers

jack black said:

Maybe I missed this But here I go What would the pressure be for a 255 Keith SWC out of a Colt SAA with a load of 9 Grains of Unique ? I keep reading it is way to much .I have used this as a hunting load 30 plus years with the same gun . Just wondering.

I thank you in advance

Click to expand...

Hi,

i dunno, but HP White Laboratory can sort it out for you. They do all kinds of testing, and are arguably THE source for ballistic testing in the US outside the gun/ammo factories. http://www.hpwhite.com/ for serious inquiries, https://www.youtube.com/user/hpwhitelaboratory for a video of some of the fun stuff they test.

You pay them money and learn stuff.

Rick C

Is it above 14k psi ? Sure.

Is it appropriate for your gun ? That's s long discussion . The writings of Brian Pearce are probably the difinitive modern era explorations of suitable pressure levels for .45 Colt , and loads within the various pressure tiers .

One common rule of thumb that involves minimal leaps of intuition involves .45acp . To wit ; if a particular gun was offered from the factory with .45acp cylinder , there would be strong presumption that .45acp pressures would also be viable in the .45 Colt cylinder .

Using that train of thought, would 9grs be suitable ? Probably .

As beloved as Unique is for its versatility , Pearce shows some alternatives . Read Pearce for specifics , but certain powders can match your current velocity at lower pressure, Or higher velocities at current pressure .

As john Lindbaugh said "velocities above 900 only add to flattening trajectory"

I am thinking 9 gr of Unique with a 255 swc run about 16,000 psi. IMHO. In my Colts cases drop out and show no sign of excessive pressure and that load at 50yds. or less gives complete pass through on deer and kills Black Bear very well with great penetration and bone crushing performance.

For inquiring minds:

The April 2022 HANDLOADER magazine issue number 337 has a feature article called "45 Colt +P Medium Frame Sixguns" written by Brian Pearce. It's all about tier 2 pressure loads that are above 14k psi for strong modern SA's.

Handloader #320 June-July 2019 has tier 1 standard pressure loads for less than 14k.