25-5 throwing slugs sideways

[amazingflapjack]

Hi everyone- I have a 25-5 8 3/8 that has been modified to use moon clips with .45 ACP's as well as .45 LC. I took it to the range today for the first time, and while it was accurate and functioned well, it was throwing the ACP's sideways. I had first zeroed the gun with the LC's, and continued to fire probably 50+ rounds of LC, and then loaded the moon clips. The ACP rounds "seemed" to kind of walk around the center of the target. I applied my trusty nylon brush to the forcing cone and the cylinder face, to no avail. I fired several moon clips through it, and the results were consistantly the same. The only thought I had was that firing the longer rounds first may have had some effect on it. When I got home and cleaned it, I checked the bore before beginning to clean it to see if anything looked "diferent" and the only thing that seemed a little unusual was what looked like more leading toward the end of the bore. I was shooting RNL and LSWC's-230's and 255"s- over Unique, the same load I use in several other guns, and it really wasn't what I would call real dirty, given the number of rounds shot-easily over 100. I would appreciate all suggestions. Thanks, Flapjack

 

[ms]

Were the bullet diameters for the ACPs and LCs the same? In my 25-5 with large throats, .454 bullets shoot much better than .452.

 

[amazingflapjack]

Yes Mark, they were all.452's, but I will check the size of the charge holes and report back. Thanks. Flapjack

 

[amazingflapjack]

charge hole size check

OK All-I got the LSWC-255 gr-Magnus bullet that was loaded in the LC's and droped it into the charge holes. It lightly stuck in all of them, and to the same depth. When I bought the gun, I asked the dealer to perform this same test with a good quality bullet. He did and reported the same results that I just got. From that point it went to a gunsmith for the cylinder modification, as well as an action job and a few other things. I have waited 6 months for this project to be completed. It is something I don't get to do all the time, and never anything like this. The 230 gr rnl bullets that were loaded into the moon clips were some inexpensive stuff that just happened to be already in moon clips, and laying on the top of the box of loaded moon clips, and unfortunately, I don't have anymore loose ones (maybe fortunately?) but because they are in .45 ACP's, I was able to take one of the loaded bullets and drop it in the charge holes. Not conclusive I'm sure, and while the bullet seemed to stick a little, I couldn't really tell if it was just indexing. So at least we know that the charge holes are not oversize, the LC's shot great, but we don't know about the lead in the ACP's. What's Next? Thanks. Flapjack

 

[tomcatt51]

What's Next?

Try some jacketed .45 acp.
Really measure the throat diameters.

 

[Frank46]

I think MS has the right idea. Fit the bullet to your cylinder throat. You didn't say what alloy was for the magnus bullet or the 45acp. So if the magnus bullet was store bought it may have been considerably harder than the 45acp. One other thing, did you clean the cylinder prior to shooting the 45acp?. There may have been enough fouling and lead deposits in the cylinder
to afffect the as loaded diameter of the 45acp bullets. Stranger things have happened. Sort of like chambering 357 magnums after shooting 38 specials in the same revolver. Fouling builds up after the 38 specials and when it comes time for the 357's you have difficult loading or they won't chamber at all. Hope this helps. Frank

 

[amazingflapjack]

Frank and everyone-The whole idea of the 2 different length rounds is something I considered. I fired the longer round first, so the only place the ACP round would be hitting fouling would be right before exiting, which could be an answer. The ACP bullets were bought from a man who makes them at home from car weights with a LEE mold. I would have to think they would be considerably softer than the Magnus. Also, I had the thought that, because they are round nose, there isn't anything on the bullet that "gets a grip" as it starts out of the cylinder, especially because they are seated down pretty good. The LSWC's have a full size portion sitting just above the end of the case to interact with the cylinder / barrel when it first starts out. I think these are the factors that contributed to the situation. Also, the round nose were lubed with Lee bullet lube, coated over the whole slug, possibly helping its ability to turn around, etc. What do you guys think? Thanks fot your thoughts. Flapjack

 

[tdan]

I'm betting that those 45ACP bullets are "tipping" a bit before they reach the chamber mouth. Keep in mind that those clipped 45ACP bullets have to start out in a cylinder chambered for the 45Colt cartridge. Any imperfection on the base of your bullet will cause a bit of tipping. This is exaggerated with the bullet having started flight from an excessively "roomy" chamber. I can certainly appreciate your mission regarding how a 45ACP round would do in the accuracy department with that long 8" + barrel.

I was curious as to this conversion on a Smith 45Colt. Seems like there is a mixed bag of reviews as to accuracy for the 45ACP rounds that the mod makes possible to shoot. I'd like to have a 45ACP cylinder for my 625-5 Classic, but I'd prefer a solution that calls for an extra, properly chambered and fit cylinder without any mods to the original set-up. Has anyone ever tried fitting a rechambered 44Mag cylinder for this modification?

 

[GLL]

Flapjack:

Consider shooting the exact same 0.454" bullet in both for comparison ! Rarely do you find a 25-5 (pinned barrel??) with 0.452" throats.

If you are interested I can send you some 454423 (245gr.) and 454424 (255gr.) SWC bullets to experiment with.

Jerry

 

[john traveler]

Your description of dual caliber .45 ACP/.45 Colt performance matches mine with several rechambered .45 Colt M25 revolvers. Accuracy went from good (appx 2" groups at 25 yds) to poor (6"-8" groups) when shooting the .45 ACP. Playing with bullet diameters did not improve group size.

This was with several guns, and many hundreds of rounds fired using Ransom rest testing.

 

[jimmyj]

What is the bore diameter?
What is the rifling twist?
Check the muzzle crown?

 

[haggis]

The most likely thing that is happening is that the bullet is passing an unsupported space after it exits the .45 ACP cartridge case before it gets to the cylinder throat. The slightest bullet yaw in this space causes bullet deformation in the throat, especially with lead bullets. Once the deformed bullet reaches the forcing cone and rifling, spin will be induced in the unbalanced bullet which will cause great instability in flight. Bullets with thick jackets (not plated) don't deform as much and will be more accurate than lead, but not as accurate as the parent .45 Colt.

How much "freebore" can you stand? Obviously, the 0.10" between the .38 Special and .357 Magnum, or the same distance between the .44 Special and .44 magnum, doesn't affect accuracy because the bullet is supported by the case and/or throat during its entire traverse of the freebore. Increasing freebore will lead to decreasing accuracy as the unsupported freebore approaches the bearing length of the bullet in the bore. Once it exceeds that, accuracy falls quickly. The theoretical difference between .45 ACP and .45 Colt chamber length is 0.417". 230 grain RNL .45 ACP bullets have a bearing length of about 0.32", so it's likely that they have an opportunity to tip in the freebore.

This isn't just theoretical guessing. I once tried to develop a .45 "Short Colt" cartridge by shortening normal cases. The purpose was to develop a cartridge that could be loaded and unloaded faster in combat games. Accuracy deteriorated as case length was shortened by about 0.020" and greater. By the time I got to 0.040", group size was more than 2X the original cartridge. I think that if I had gone to 0.050", the bullets would have keyholed.

Things that may make your conversion work better...

• Jacketed bullets rather than lead.
• Flatter bullet shapes (WC Better Than SWC 'BT' RNFP 'BT' RN). Shorter bullets of the same weight have more bearing length.
• Heavier bullets of the same shape have more bearing length.
• Longer .45 cases - use .45 Winchester Magnum cases in your moon clips. That will add about 0.30" to your case length and reduce your freebore to about 0.12", which should be sufficiently accurate. You could try .460 Rowland cases, but they aren't as long as the WinMag.

Buck