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Case Bulge, is this it? And, should I worry?

7502 Views 24 Replies 10 Participants Last post by  John Kort
I am working uo loads for my new production Winchester(miruko) 1892 in .45 colt. I am using new brass (Win) and 300gr Nosler Partition HG bullets. Powder is Lil' Gun. I noticed that about .35" above the rim is a nice little raised area that extends about 3/4th of the way around the shell case. I am wondering if this is a "pressure bulge" indicating I am to hot in the loading department. I am loading with 19.5 gr of powder up to 23 gr of powder. I checked the velocity of the 21.0 and 21.5 gr loads at 1438 and 1488fps.
Here is why I DON'T think it is a pressure problem but I want to get many more opinions,1)It is on all cases the exact same no matter the charge. 2) it is not a random "round" bulge, but an a very precise inverse Bottle Neck. It looks like the neck on a bottle neck cartridge(.30-06) only it is the other direction. A definite slight angle outwrds and then the rest of the case is that "new"size.
My theory is my chamber is cut poorly, allowing these reletively higher pressure loads to deform to the shape of my sloppy chamber. Comments please.
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Very interesting stuff. Why does Hodgdon say the max .45 loads are 20.2 grs? that only gets 29,800cup and 1203fps from a 7.5" gun? People do much higher then that with lots of different powders. Even factory stuff is plenty hotter then this(Cor-Bon, Buffalo Bore, Garrett.) I loaded a couple well above 20.2gr. Here is the results.
From my 5.5 in Bisley 23.0gr = 1253fps, 23.5gr=1272, 24.0gr=1337. In my '92(20") I got 23.5gr=1616fps,24.0=1672.
So what makes this amount of powder safe with 110,296 and others but not with Lil' Gun? I got 1175fps from my 5.5" with 21.5gr of Lil' Gun.22.0gr gave 1208fps. I think I will settle around there for my final load.
The recoil from my .41 with the Cor-Bon is stiff. It makes my knuckles hurt. However, I would only use those for hunting. I won't shoot very many.
I still don't understand how The three Factory Custom loaders can get 1300+ from there 6" guns safely but I have to stop at 20.2 gr and 1203fps from a 7.5"(Hodgdon Lil'Gun Load)
In looking at the Hodgdon data, my guess is that they don't want to go over 30,000 CUP in the 45 Colt for modern strong actions. It may be a brass restriction, not a firearm limit. I don't now enough about your rifle to assess the Colt in that application. Again, try the trimmed 454 Casull brass to cure your case bulging. If this works, find out the pressure limits of your rifle, and work on up.

If anyone out there knows the CUP or PSI limit for CUB's rifle, please pitch in.
Hi. Loader:
IIRC, Ross Seyfried says the Blackhawk cylinder is limited to 30,000 psi in .45 Colt. The limit's 40,000 psi in .44 Magnum cylinders, but they're getting a mite thin time they're reamed out for the .45.

Lil' Gun loads in the .357 Magnum are a bit strange too.


It may be as simple as Lil'Gun not being able to get quite as much performance as H110/WW296 (or other powders) in this example. On the other hand it is supposed to be easier to ignite, so in the real world, it may be superior in certain conditions such as hunting in cold weather. Be safe and don't get too carried away with those loads.

Both Jack Monteith and Kcih have the answers for you. I had this same problem you are describing many years ago when I bought my first Ruger Blackhawk. Tha area forward the case web was expanding to .487" with my handloads. I called Ruger, thinking that I had oversized chambers. I was informaed that the SAAMI specs allowed chamber diameters up to .492" or thereabouts! SAMMI may have tightened up the tolerances since then.

I used .005" thick tape cut about 1/16" wide and placed it around the case just forward of the rim. That centered the case in the chamber and one firing from a heavy handload expanded that case evenly all the way around. I then removed the tape and neck sized only with a carbide die to about 1/16" below where the bullet base would rest when seated. This method has worked for me for the past 25+ years.

The only downside this is that you have fireformed your cases to one gun and if you have additional guns chambered in .45 Colt, they may not fit. In my case I was lucky. I now have 3 Rugers in .45 Colt and a Marlin Cowboy and their chamber dimensions are close enough so that I can use the expanded brass in all 4 guns.

Oh, one another thing. Some bullet seating dies may not be quite large enough to allow the expanded case to be used. That was true with my original RCBS dies purchased 30 years ago so I bought some Lyman dies and they worked fine. Tat was almost 3 decades ago and dimensions may have changed since then. If the fireformed cases will not fit into your current seating die, you could have it modified or try a fired case into other die sets and purchase the one that works.

Good luck,
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