Marlin 1894 44 mag pressure signs?

[bocefus78]

Hi all,

I have been working up a load for my lever gun and need some help. Its a real JM marlin if that makes any difference.

I loaded up some new starline brass with 22 (min charge), 23, and 24 grains of 4227 with horn. 240gr xtp and federal mag primers. Heavy crimp. Max is something like 24.5gr IIRC.

In all cases, from min to max, I had a line all the way around the bottom of case that was definetly expanded a little. Forgot to take a pic-I will tonight.

Primers looked fine.

Are the chambers on these rifles a little larger at the back end for easier feeding than say a ruger SRH cylinder? The same loads had no bulges at all from the revolver.

I know a pic will help and I will post one tonight, but for now, can anyone vouch for the chamber sizing, or anything else that would give me a line all the way around the case 1/4" from the bottom of case?

Are these rifles known for not taking near max loads?

Thanks.

 

[g.willikers]

Here's a few things to try:
Load some lighter, mid range or lower rounds, and see if they get the same indications of the line and case expansion.
If it's a chamber problem, the lower pressure fired cases should still look the same as the others.
If so, check to see if there's a corresponding mark on the inside of the cases, too.
Use a small probe to see how deep the mark goes into the cases.

 

[bocefus78]

Win white box does the same thing FWIW

 

[g.willikers]

White Box is kind of mild, isn't it?
If so, then it's not a high pressure problem.
How old is this rifle?
Might be time to do a chamber dimension check.
http://www.midwayusa.com/product/462291/cerrosafe-chamber-casting-alloy-1-2-lb

 

[bocefus78]

Made in 2006 IIRC.

Fired less than 200 shots.

 

[gamestalker]

You loads all seem to be well within the published tables at both ends.

Cerrosafe is a great chamber casting product, but before you buy it for this chamber, take some fired brass measurements and compare to SAAMI spec.. If the expansion ring is that pronounced, I'm pretty certain it can be determined by measuring the brass alone. And then if the brass confirms your suspicions, you can then do a casting to see just how far out of spec it is.

GS

 

[buck460XVR]

Hornady shows a 24.2 as a max load in 44. rifle withIMR4227 and a 240gr XTP. I doubt if what you are seeing is excessive pressure if the rounds are extracting without too much difficulty and primers look good. What you may be seeing is the slop from the bolt resulting in excessive head spacing and the stretching of the case because of it. Levers lock up at the rear of the bolt, thus the bolt flexes when shot. Because of this, especially in straight walled handgun calibers, the cases stretch. This is why many manuals recommend using only virgin or once fired brass for max loads in handgun caliber lever carbines. Loading cases too many times with max loads will stretch the case and lead to case head separation.


..or it could be a bad chamber ream.

 

[bocefus78]

Here Is a pic. One on left from marlin. One on right from srh.

Expanded area measures .4615 on the worst one of 25 shot.

 

[bocefus78]

Mods...I'm thinking this is a chamber issue and not a loading issue. Can we move this to long guns for a new set of eyes?

Thanks.

 

[buck460XVR]

There seems to be blowby at the cartridge rim, and the brass seems to be expanded as if the base of cartridge is in the relief in the chamber for the rim. I wonder if your bolt has too much play at lock-up.

 

[MEHavey]

Same thing on my `94Marlin 45Colt. (also JM)
Discernable bulge at the base of one side of the
case, where the thicker web quits, after heavy
bullet/higher Ruger-pressure loads (340gr Cast/1,500fps).

I judge it to be a chamber relief issue designed for reliable feeding
coupled w/ the extractor holding the case to one side of that relief.
It resizes out.

 

[dickydalton]

My Winchester 94 45 Colt does the same thing.