44Mag Pressure?

[Forester]

I have a S&W Mountain Gun my wife gave me last Christmas, I have tried a handful of powders and bullets with the gun but it always shows pressure at powder charges at the bottom end of the load books. Powders include: 800X, 231, Clays, and HS-6 (All powders I had on hand) I have tried both Jacketed and Cast with the same results.

For example, with H110 and Hornady 240grXTPs I have to drop 2 grains below the Hornady book just to get to a load that only shows some primer flattening.

The crimp was what I would call middle of the road, hard to quantify with a roll crimp. I did not start below book loads, but with a load right in the middle of what a couple different books recommend the primers were flattened, dished, and generally looked like WAY to much pressure.

I used to load and shoot 25-30,000 rounds a year worth of 9mm, 40S&W, 45ACP, and 38spl. when I was shooting USPSA and IDPA regularly so loading for a handgun is not new to me, but I have never seen a handgun behave this way.

Any ideas what could be causing this? Sorry no Chrono data yet to see if the pressure has corresponding velocities.

[RobS]

Did you check your cylinder throats and barrel diameter as if they are smaller than normal specifications this could increase your pressures? Just a thought anyway.

[felix]

The powder is being ignited too well in comparison to your other guns. Fat boolits, hard boolits, etc. Also, you are using a different caliber than what you are used to. Velocity would be interesting, but no real proof of anything. Check the diameter of each cylinder hole with a new push through oversized boolit and compare that to the diameter of the condom you are using. ... felix

[AZ-Stew]

You might have a gunsmith check your revolver for exessive headspace. If the primer can back out before the powder ignites, the case will then be forced back on an already expanded primer and make it look like excessive pressure.

Regards,

Stew

[thenaaks]

headspace...hmmmmmm....a set of feeler gauges could tell you what you've got...surely someone else has a mountain gun to compare it to.

i get some primer flattening with my 240gr cast boolits and a mid-range charge of titegroup. i figure that my seating depth and oal are ok, and i'm within spec for powder charge, then it's no big deal. shot lots of 'em with no problems.

[runfiverun]

mashed primers indicate the cases are moving backwards.
how are the cases coming out of the cylinders?
are there a lot of marks on the cases? rings around the brass,sticking?
you probably aren't producing enough pressure for the case to grab the case walls.

[Edubya]

Load'em at maximum COL.
Stretch a case so that it will just barely fit over the boolit head, start the boolit in the case and drop it in the cylinder. Gently remove the cartridge and measure the COL. If the lube groove is inside of the case, try a couple of rounds with that COL, even if you have to taper crimp.
If you're using a target load, this is sufficient.
EW

[MtGun44]

"Some primer flattening"?????

May or may not mean anything. What primer and how flat? Certainly you will absolutely
get significant primer flattening with any normal .44 Mag load as you get near the top
of the pressure range. Also, primer flattening is a totally unreliable "pressure sign".

Given normal dimensions of the barrel, throats and chambers and a check on your
powder scale with an accurate check weight, I'd forget it and carry on.

[sagacious]

"Some primer flattening"?????

May or may not mean anything. What primer and how flat? Certainly you will absolutely
get significant primer flattening with any normal .44 Mag load as you get near the top
of the pressure range. Also, primer flattening is a totally unreliable "pressure sign".

Given normal dimensions of the barrel, throats and chambers and a check on your
powder scale with an accurate check weight, I'd forget it and carry on.

I agree completely with the above quoted commentary. A full-power 44Mag load will often show F-L-A-T primers, but that is normal and not at all a discriminator for dangerous pressures. Your concern is completely understandable, as one might not routinely experience this with 9mm, 40S&W, 45ACP, and 38Spl loads.

Verify your reload data and charge weights, and proceed. Good luck.

[Forester]

OK, I will load a few working up and shoot them over the chrono. I will take some pictures to post here.

If what I am seeing is normal for a 44mag then great, learned something new. But I would have called the primer flattening more along the lines of extreme than "some"

If anyone has a mountain gun they can check headspace on and give me a number that would be great. I should be able to check mine this evening.

[Forester]

Just an update, a tighter crimp seems to have solved the problem. The primers dont look so bad now though still plenty flat. Velocities with a 240gr boolit are running about 1150fps.

The upside instead of having difficulty keeping shots on an 8" plate at 25 yards it is now no real trick to go 6 for 6 on that same plate at 60 yards. (different grips, a spring kit and some light trigger work helped that too)

Thanks for all the suggestions and help!

[fredj338]

Are the cases sticking in the cyl? As noted, there are flattened primers & then there are flattened primers. I 've loaded & shot 44mags for decades now, even wore out a RSBH shooting met sil. If you get flattened primers & sticky case ext, something is going on, but sort-of flattened primers, not really an issue. BTW, flattened is when you can not see any gap at all between primer cup & pocket, almost seemless. That is a pressure issue.

[Forester]

Are the cases sticking in the cyl? As noted, there are flattened primers & then there are flattened primers. I 've loaded & shot 44mags for decades now, even wore out a RSBH shooting met sil. If you get flattened primers & sticky case ext, something is going on, but sort-of flattened primers, not really an issue. BTW, flattened is when you can not see any gap at all between primer cup & pocket, almost seemless. That is a pressure issue.

The problem seems to be solved now, they were not quite to that "seamless" point, I know exactly what that looks like from a rifle we don't need to talk about:shock:

The cases were never sticky in the chamber either so I think I was worried about nothing.

I cast about 800 429421s today and lubed them, they shot great over H110 but a full house load was downright miserable to shoot. Accurate as can be though.

I loaded some over 4.7gr of Acc.#2 as well and they are not as accurate but plenty comfortable to shoot. I may pick up some unique and try to hit a middle ground, who wants a 44mag that feels like a 38spl anyway?:bigsmyl2:

[spqrzilla]

Sometimes what are actually low pressures will make primers look "flattened". The tighter crimp solving the issue makes me think that you were getting inefficient burning of the slower powders.

Great that you found a solution.

[fredj338]

I may pick up some unique and try to hit a middle ground, who wants a 44mag that feels like a 38spl anyway?
I hear that. I have a nice "little" 629/3" that is a hoot to shoot, but brutal w/ full power loads. It does quite well w/ 250grLSWC o/ 9gr of Unqiue for about 950fps, pleasent. My serious load is a 270grLHP w/ 19gr of 2400 for about 1200fps in the short bbl.