45 Colt gas seal

[Nobade]

I just started playing with a Marlin 1894 in 45 Colt yesterday, and experienced what others have mentioned in the past - the cases don't seal the chamber even with full charge loads of BP and certainly not with any factory smokeless loads. So what's the secret? I'm thinking that anealing the cases will help, I'm going to try that first to see if I can get them soft enough to work. I wonder why the factories feel the need to make them so thick anyway?

[RayinNH]

Seems like it would make more sense if Marlin just made the chamber the right size...Ray

[Bass Ackward]

There are four secrets of which you nailed the first. Anneal. But you can only go so soft. You need some spring back to be able to have the case let go of the walls to extract.

The second is to make the brass not have to go as far to fill the chamber by partially full length sizing your brass. If your chamber is at least round, it should not impair operation. The only draw back here is that you need to maintain bullet tension by also doing the third method.

The third is to load / shoot as large a bullet that will chamber. This will keep the brass closer to the chamber wall so it doesn't have to expand as far.

The fourth is to shoot softer lead so obturation can occur at lower pressures and possibly obturate while still inside the case. The sooner it seals, the more pressure you will have to perform the expansion of the brass.

[w30wcf]

Bass Ackward,

Great advice! [smilie=w: I couldn't have said it better myself. Having shot the .45Colt since 1974, I have found these techniqes to work very well.:-D

w30wcf

[berkmberk1]

Sounds like you could use what I've been looking for in a pistol bullet.........an original style 250-255 hollow base. Seems I read somewhere, maybe a Keith book, the original load for the 1873 SAA had such a bullet. The primary reason for the design was that the BP impulse at detonation would expand the skirt of the slug to fill the bore and seal it, making as full a use of the charge as possible.

[lar45]

I took a 45 Colt case and ran a 45 acp expander all the way down to the base to over expand it. I then sized it in a Lee 45 Colt factory crimp die wich left the case at .480". It fits my Fat Ruger cylinder perfectly. 44man was talking about neck sizeing and leaveing the base alone. How big is the chamber on your Marlin?
the suggestion about a larger soft slug sounds good to me. Aneal the case mouth and give it less distance to expand.

[Nueces]

lar45, you da man! That just lit up my dim bulb, thanks!

Mark

[Nobade]

Thanks guys, this is pretty much what I figured to do. That Marlin does have a rather large chamber, the fired cases are nearly as large as the rims! For smokeless loads I have been partial sizing just enough to hold the bullet, then running them through the expander die. For black powder loads it's even easier - deprime, wet tumble, reprime after drying, bell the mouth just enough to remove the crimp, throw powder, seat bullet by hand, and crimp. They shoot better than smokeless anyhow, so I'll stick to that.

[Dale53]

Ed Harris has suggested on most pistol rounds, using BP or fast burning pistol powder (target loads) to NOT resize the cases (just decap using the Lee Universal decapper). Use relatively large "as cast" soft bullets, and final size in the Lee Factory Crimp Die. The crimp should keep the bullets from "deep seating" from magazine spring pressure and the cases being quite a bit larger before firing should seal well.

Most full length size dies over size the cases which aggravates the problem of a large chamber.

A bonus doing things this way, is extended case life and much easier sizing (none) and case neck expanding.

Dale53

[Chuck 100 yd]

Nobade, I have two Marlin 1894`s in .45 Colt and have had the same problem when shooting low pressure loads. The chambers are .011 and .012 " larger than the resized cases from my RCBS dies.
A good stiff load of H110 or Lil-gun will not smoke cases but 8-9 gr of Unique or any load at that level sure will.
Try just resizing your cases part way (length of the bullet). This works good if you dont want to shoot hot loads.