Need help with a SAA problem


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warddc
October 22, 2004, 03:39 PM
I bought a new cimarron 45 colt model P in stainless. The problem is that after only a few cylinders of ammo the cylinder binds at the rear due to soot buildup. The brass comes out filthy all the way back to the head. The area behind the cylinder where the action is, gets gummed up and you have to wiggle the cylinder to get it to rotate. The cylinder to barrel gap is 0.010" which i thought was a little large. I am shooting reloads and have tried about 10 different powders (231, tightgroup, unique, universal, bullseye, etc...) and several different bullets (meister 200 gr LSWC, Excel 255 gr RNFP). The gun has gone back to cimarron but they say everything is in spec and shoots fine after 30 rnds of black hills 250 gr.

Is there anyting that can be done to fix the gun or are my reloads the problem? I did not try to shoot any commercial ammo in the gun before it was returned. I have reloaded many calibers for many years and didn't think that the ammo was the culprit but...

Any ideas?

dave.

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Vern Humphrey
October 22, 2004, 08:26 PM
What charges are you using in these reloads?


When you say, "The brass comes out filthy all the way back to the head," that suggests the brass is not obdurating -- which may be due to too light a charge.

Jim March
October 22, 2004, 09:25 PM
What Vern said. The brass is supposed to expand into being a "plug" keeping all gasses forward of the shell's rim. If that's not happening, then there's not enough pressure to make the seal.

A .010" gap is "in spec" but...:barf:...well, don't worry about it, as I assume this isn't a self defense gun. Accuracy should still be OK. I wouldn't accept that on a "real business weapon" :scrutiny:.

Bad Flynch
October 22, 2004, 09:37 PM
Here are some suggestions from a fellow who shoots many .45 Colts.

Vern is right about obturation of the chambers. The .45 Colt is famous for having this problem and the result is dirty chambers, etc., just like you have.

1) Heavier bullets obturate better, so shoot 250 grain bullets.

2) Switch to brass with less capacity and brass that is softer, like Remington cases. Softer cases swell up better and seal.

3) Shoot higher pressure loads with faster powders and use powders with reputations for giving clean burning. Make your loads about at SAAMI maximum pressure (13000-=14000 psi range) and make sure that you have a good, tight crimp. That means that your velocities will approximate standard .45 Colt factory loadings. Higher is not better.

4) 0.010" BC gap is not excessive for a revolver meant for lead bullet shooting, but does contribute to the fouling problem a little.

If you do those things, your luck will improve. In addition, the gun may be a little tight. If the cylinder has ablsolutely no end play, have a gunsmith introduce 0.0005" or 0.001" end play (a half to one thousandths).

warddc
October 23, 2004, 03:13 PM
No this isn't a self-defense gun. I just bought it for some fun with targets.

Maybe my loads are a little light. I was trying about .5 gr less than the max listed for each load. I am using new remington brass. Here are some of the loads I tried.

These are all with an Excel 255 gr LRNFP

5.8 gr Tightgroup (max listed 6.3)
7.6 gr Unique (max listed 8.0)
5.0 gr Bullseye (max listed 5.4)
5.4 gr Solo1000 (max listed 5.8)
6.8 gr Win231 (max listed 7.2)

My crimp was what i would consider moderate not heavy. There is some end play in the cylinder. I would guess it to be .001" or there abouts.

When I get the gun back, I will try hotter loads near max and use a heavier crimp.

Bad Flynch what powder and load should i be using?

d.

Jim K
October 23, 2004, 08:41 PM
Those loads seem OK, so you might work on using more crimp as a means of increasing pressure. BTW, I have use both your Unique load and your Bullseye load with no problems.

.010 is a bit more gap than I like, but it is in spec and good for action shooting games where one problem has been cylinders with tight b/c gaps binding when they get hot. I doubt it is causing your obturation problem.

Jim

Jim March
October 23, 2004, 09:03 PM
This is actually somewhat puzzling. You *should* have enough pressure here and I agree, it ain't the gap at fault.

:confused:

I'm wondering if your cylinder throats aren't oversize? *Something* is dropping pressure...it's either that or your crimp...or both?

Mannlicher
October 23, 2004, 10:45 PM
For what its worth, I also had a lot of trouble with moderate loads in my Ruger Vaquero: sooty, dirty brass, until I increased the crimp. Groups got smaller too.

Traveler
October 24, 2004, 12:10 AM
Have you checked to see that the the chambers are in spec? I have seen some that were grossly oversized. This would account for some of the problem. Another problem could be excessive tolerence between the cylinder and the pin. Powder and debris getting in there tends to slow things down.

warddc
October 24, 2004, 12:10 PM
I was thinking that maybe the cylinders were too large as well or that the cylinder throat was oversized. I can't remember what the cylinders mic'd to but I remember that the cylinder throats were 0.455". I thought that the cylinder throats were supposed to be slightly smaller or equal to the bullet diameter. I mic'd the bullets. They are .453". I also thought that the cylinder walls were VERY rough but I was told by cimarron that the roughness is normal for these guns. If the cylinders were not polished the brass would have a hard time sealing wouldn't it?

dave.

warddc
October 25, 2004, 09:08 PM
Cimarron has agreed to replace the gun. I guess they figured whatever was wrong with it would not be able to be fixed and replacement would be quicker and easier. Hopefully the new gun will perform better.

D.

SASS#23149
October 26, 2004, 02:35 AM
'rough' is subjective,but certainly not 'normal' in a revolver.Should be smoothe at least.
sounds like your loads are fine,I shoot a lot lighter loads in cas matches with a little sooting on the cases but not near what you describe.I've never had a gun jam up due to that much residue during a match or shooting session.
Sounds like Cimarron is a stand up company.In general their guns are thought highly of.Guess anybody can make a mistake.Making it right is what gets noticed.

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