Soot on your fired cases? If so, too low pressure. Increase powder charge( may not keep you SASS legal) heavy crimp and heavier boolit may help? Chambers seem to run large.
Similar issues with mine with low velocity fodder.
Papalote

 

As mentioned the Marlins have generous chambers and only heavy loads will expand the cartridge enough to seal the chamber. However it isn't just a Marlin problem as some the other guns will do the same due to that big fat case simply not expanding well with cowboy loads. Heavier loads won't do you for SASS so about the only solution I can see is to just neck size the first 1/3 of the case or go to a cast size that doesn't require you to size the case.

The other solution is to use Trailboss which creates more pressure at lower velocities that most other powders. Couple Trailboss with a heavy crimp just might cure your problem.

 

Anneal!!!

Soft cases pack tight.

 

The .45 Colt has straight walls, needs a certain amount of pressure to expand and seal. Powder-puff loads won't do that. The original .44-40 chambering is bottle-necked with a slight taper and has thin case walls, no problems with low pressure loads sealing with that. Marlin's oversized chamber doesn't help, maybe just sizing the case down to the bottom of the bullet would help. It'd mean your reloads would probably only chamber in one gun, though. Some runs of 1894s had divots on the bolt's chamber end sides to release gas, is your gun made that way? You could also gear up with a tubing micrometer and look for case lots with thinner walls.

The large chamber in .45 has had some past discussion here, my feeling is that it's deliberate to allow a stubby straight wall case to reliably feed. To me, it's telling that no one chambered a repeater in .45 Colt until modern times. The original skinny rim diameter was one problem.

Stan S.

 

Shot a Rossi that did that once. At one time Starline offered 45 Colt "rifle" cases. Alightly larger rim? They advertised more positive extraction so they would not help much. Always heard they needed to be loaded heavier to seal the chamber also.

DEP

 

Did i mention that you have to anneal your cases?
If they are reloaded umpteen times brass will be workhardned and absolutly needs to be annealed. Not to mention that rock hard brass will size down lead bullets when they are seated!

 

I've loaded NEW! Winchester and Starline brass for the 45 Colt for my 1894, it took a 250grn boolit and a MAX charge of TrailBoss to get it to seal up!
Annealing may help??, but the chamber are VERY GENEROUS! you MUST load them up to get them to seal up!

 

I am glad to see this post. I have been loading my 44's and 38/357's up for my Marlins and have not had this problem but they are all loaded close to max anyway. But if it happens I know what is going on now.

 

I have had this problem with my 45LC CBL 1894 also. My load was 7.7 gr 231 with a 255 gr cast RNFP, @ 1050 fps. Traditional ballistics out of a rifle. It boils down to generous sized chambers and low pressure loads, that do not expand the case enough to seal the blowback. My solution to the problem, is to back off the sizing die, to size only the top 3/8" of the case, or just enough to grip the bullet. The added diameter of the rest of case, tends to seal things off better, so blowback is a non issue. It's something worth trying to see if it cures your problem.

 

In addition to the excellent advice above, I would suggest no less than a .454" diameter bullet on up to a .456" diameter bullet (original bullet diameter) which will reduce windage in the chamber.

I have been loading the .45 Colt since 1974 and I learned a long time ago to just neck size my brass to 1/16" below where the base of the bullet rest and leave the rest of the case expanded to reduce the windage.

According to SAMMI specs, 45 Colt chambers have a bit more "windage" than most other cartridges. In otherwords, more than just a bit of clearance between the diameter of the unfired case and the chamber. That bit of extra space allows soot to get back onto the outside of the case especially with low pressure loadings.

Most other cartridges have about .007"maximum "windage" in the chambers, but in the .45 Colt it can be upto double that amount! (.491" max SAMMI chamber spec (rear) / .475"case diameter). Neck sizing only really helps in addition to annealing.

w30wcf

 

I started a thread on this subject not too long ago, but I can’t find it. Might have been on a reloading forum, but lots of good info in this thread. I’ve only had the gun for a couple of weeks and only shot some 255 grain FMJ’s from Freedom Munitions and there is a ton of black soot on the cases. Today will be the delivery of the last factory ammo, then I have about 6 or 7 different cartridges to shoot to get a feel for what the .45 Colt is capable of, including some HSM Bear Loads. A 325 grain +P gas checked bullet.

I have powder, primers and my dies arrive today. How does one only neck size a straight walled case? Back the die out till it no longer touches the case then dial it in a bit at a time till you get the depth of resizing you want?

 

You got it, that is how to set the amount of re-sizing you want. Good luck! DP

 

Yesterday I put a bunch of different factory ammo thru the gun and got a ton of black soot on all the cases until I got to the HSM Bear Load. A 325 grain +P load. While I got a little soot, it wasn’t much. Then I shot some Buffalo Bore 260 grain +P stuff. My shoulder is still red from shooting that stuff, but it left no soot on the case. That suff was 1883 fps @ 2026 fpe. Not something I’ll be shooting very often. The HSM stuff was 1355 fps @ 1234 fpe. Everything else was 1100 fps and under and left a ton of soot on the cases. I’ll definitely have to try the neck sizing trick before I get too deep into reloading the .45 Colt.

 

There is off-and-on discussion of 45 colt reloading quirks in HANDLOADER or RIFLE magazines. One suggestion was to get custom sizing dies made off the dimensions of a chamber cast or fired brass from your rifle. No carbide dies and a PITA lubing and cleaning cases!
I'd start off by buying oversize bullets, then try annealing your casings. Neck sizing only with carbide dies wouldn"t be a bad choice either...and save the case lube hassle.
IIRC, some gun scribe went into some detail about case set back in 44/40 COLT revolvers using factory ammo back in the 1870/80 era. The factory solution was to make brass thinner...end of problem except case life was extremely limited. HOWEVER, if I was having a disagreement with unhappy native americans back in the day, I probably wouldn't be picking up my brass or worried about future reloading problems. Someone may tell you which 45 colt brass is thinnest and you could try that.

 

Many of my friends who have lever rifles chambered in .45 Colt have had to deal with this problem. I'd start with a heavy bullet and go from there.

 

Been using a 45 LC load of 22 grns Win 296 with a 280 grn hard cast and a heavy crimp with a Lee factory crimp die. Works great in both my Ruger 45lc Blackhawk and my 1894 Cowboy Limited. Same load for both guns.

 

Here's a pick of neck sized .45 Colt Cartridges. They had been fired previously, then neck sized.
Bullet diameter: .454"
Brass: Starline

One may need to use close to or a max. standard 45 Colt load with a 250 gr. bullet in new brass to get the cases to expand to the point that they take up most of the windage in the chamber. Personally, I use 6 grs of either Bullseye or Titegroup, or 7 / 231 or 8 / Unique.

I pretty much goes without saying but cases fire formed in one gun may not fit another. I am a bit lucky in that the fire formed cases that fit my Marlin, will also fit my 2 Ruger Blackhawks. They will not fit my Colt clone which has tighter chambers, so I use a different brand of brass in that gun.

w30wcf

 

My 94 cowboy in 45 colt gets same problem----light bullet weight or too small o load of powder & ya get blowback----I tried a bunch of different remedies bout crimp & such--still got it-----using 250 gr lead never any blowback----light powder charge or heavy-- went to useing-for sass use 250 gr bullet--TrailBoss powder & ya ready to go----light recoil-no blowback & still will knock down knock over targets!!