.45 Colt Update...

[theozzman]

Hey guys, long time no see.

So a while back i posted about my Rossi 92 in .45 Colt. I was having bore diameter issues, trouble finding the right projectile, unburnt powder etc.

So I finally got around to getting some calipers so as I could measure the balls when I slug my bore. I slugged her, with readings at .450 and .451 at largest. I put the variability down to my inexperience with calipers.

This result was a surprise to me, as I assumed it was .454 or similar, due to it performing very poorly with .452 and the like.

I discovered the issue (I think) whilst slugging. The .454 round ball (From my Walker Colt) went in the bore tight as would be expected, but when approximately mid way along the bore, resistance on the rod pushing the ball dropped....it almost dropped several inches without any hammering, the when it reached the throat it got tight, tighter than when at the muzzle.

So, based on this and advice from someone else, this is my hypothesis; the bullet (whatever diameter) goes through the throat area and is sized down, then travels the rest of the bore not fitting properely as the throat has sized it down smaller than the rest of my bore.

If this is true, I am thinking I have 3 options; new barrel, chamber reaming, bore sleeve.

I would prefer to get a new barrel, but being a half round, half octagonal 24 inch, this might be tricky. The sleeve may be easier. Not sure about reaming, as the projectile may still allow gasses to escape past before it hits the tighter part of the bore.

What do y'all think?? It is such a dissapointment as I have done alot of work on the gun, slicking up the action, trigger lightening mods, refinshed the dark Rossi wood to a nice light finish. Plus it holds 13+1 of my favourite calibre AND I have just bought a brand new Uberti Cattleman in, yep, you guessed; .45 Colt I love the lever gun and the Uberti and can't let this lever gun go!

Thanks for taking the time to look at my topic, even if you can't help, thanks anyway. I hope my grammar is clear enough.

theozzman from downunder.

[earlmck]

Ouch! That does sound like the bore is not shooter friendly. Before doing anything drastic I might explore a few more ideas. First thing you can do is fire-lap the bore, using unlubed cast bullets with the lap grit pressed in (lap kits come with directions for this. You shoot these so they just poop through the barrel, probably use about 2.5 grains of your AS30 (for you old US reloaders, AS30 is real close to Red Dot for character).

Next thing is that you don't want "hard cast" bullets for these light loads, and even that AR2205 load you mentioned in your first post is pretty light and might like a softer bullet better.

And third, I'm guessing that the reason your bore is so tight down there near the chamber is because it is getting too much "squeeze" when turned into the threads of the action. I'm thinking a good gunsmith could rework the action and/or barrel threads to relieve some pressure and that would help a great deal. A barrel that just gets a little tighter toward the muzzle should work just fine for you. It seems to be real common for revolvers to have a tight barrel diameter where it screws in to the frame, and I helped a 44 Ruger out quite a lot with a lapping session (about 50 or 75 shots worth as I vaguely recall) and never did have to go to the gunsmith.

Then as a last resort I would look at a barrel re-line. But that tightness where she screws into the frame would still need to be relieved because that would also affect the newly lined barrel, I suspect.

And I should say it is good to hear from you again theozzman. We old levergunners do love to sit around and theorize on puzzles such as you present.

[BigSky56]

Ozz
Earl is on the money on this I would suggest you fire lap your barrel I have down this with my pistols and rifles and it works, barrels can have minor flaws and constrictions at dovetails, pistol barrels are sometimes constricted where they are threaded into the frame there is a treatise on how to do fire lapping at http://www.lasc.us/Brennan_Fire_lapping.htmand at Beartooth Bullets site http://beartoothbullets.com/. danny

[Les Staley]

Is sending it back to the Importer an option? I sent a puma back to LSI twice for barrel replacement and the second time was rebarrelled ..shot worlds better..two inch groups at 100 yds.. From paper plate sized patterns .

[Thunder50]

I would try the firelapping first. See how that works. You could also cast a lap and work down on the breech end of the rifle and see if you could get rid of some of any remaining constriction, left over after firelapping.

If you do have to re-line, then it would be better if the barrel was drilled while still attached to the frame, that way you could get rid of any constriction where the barrel screws into the frame.

[Mescalero]

I don't know about drilling and relining that barrel, does'nt seem to be a lot of wall there to start with.

[ulav8r]

The threaded portion of the barrel does not extend past the throat, does it. Hand lapping would allow you to concentrate on the tight portions and even out the diameter end to end.

[Nate Kiowa Jones]

Are you sure your load is warm enough to expand the brass to provide a good seal? The 45lc rifles are notorious for generous chambers sizes and tend to blow by if the load doesn't expand the brass enough to seal. If it blows-by you get inconsistent pressure and poor accuracy.

[Tactical Lever]

Tell Uberti that that you want your rifle rebarreled, not a new one, as you have put a fair bit of work into it.

They should fix it.

[theozzman]

Thankyou fellas. I truly appreciate the help and general kindness I receive here, it is second to none.

Earl, I will look into fire lapping as a first step, I like the sound of that.

Nate, the load may be a bit light I guess, but even when I have used heavier loads, things did not improve. My concern mainly is the bore, I am hoping to remedy that, then tweak my loads. I will keep that in mind my friend.

Les, unfortunately I bought the gun second hand and am not sure who imported it

I am going to read over and absord the advice from all here and plan my course of action.

Thankyou to everyone, I appreciate your time.

Ozzman

[theozzman]

Just a quick addition, would reaming the chamber help? I figured if the chamber/throat is sizing the projectiles down, maybe opening it up would help. I theorised that it would prevent the sizing down and get good seal etc...

[Nate Kiowa Jones]

Just a quick addition, would reaming the chamber help? I figured if the chamber/throat is sizing the projectiles down, maybe opening it up would help. I theorised that it would prevent the sizing down and get good seal etc...

Ok, first, are you absolutely sure the bore is lead free. Normally leading occurs from just in front of the chamber on out but is less farther down the bore. That could explain the restriction.

The way to know for sure is scrub the bore with an old bore brush wrapped to fit tight in the bore with some bronze wool, (steel wool can be too harsh) Do this with the gun upside down over a sheet of white paper so you can see the flakes of lead.
Next, is your bore slugging method may be giving you a false reading. Here's how I like to slug a bore. I like to use a slug of soft lead that is at least 1 1/2 times long than the bore dia that's being slugged. for a 45lc that's about 3/4". This extra length assures that the slug doesn't wobble or try to turn in the bore as it's hammered through. This can be verified with short slugs. Measurements will vary depending on where you measure it. The longer slug yields more consistent results. Make sure the bore is clean lead free and lightly oiled, as in an oiled patch pushed through it.
You can drive the slug in from the muzzle if you use a leather or rubber mallet so as not to damage the crown. I like to drive it all the way through to feel any high spots or bulges. I like to use a brass or hardwood dowel that is close to bore size. A rod that is too small can deform the soft lead. Next in a levergun I use two wooden dowels just smaller than the bore and cut to the cartridge OAL. These are inserted into the chamber end and the action closed. Next the slug is re inserted in the muzzle end and driven to the wood dowel then bumped up so it's now tight. Now, open the action, remove the dowels and gently tap the slug on out. This will give you a really true picture of the bore just in front of the chamber or farther out depending on how many dowels are used.
To measure I like to use a zero-ed Starret micrometer. Most dial calipers aren’t accurate enough.

Now, once you have done all this and you are sure the bore is still tight in front of the chamber you best option then is to fire lap it.

[hightime]

I sent mine back after a year and they gave me a new gun. Both were tight near the chamber then tight near the rear sight. The second rifle was a much better shooter, but I still lapped the tight spots.

Owen

[theozzman]

Thankyou Nate and hightime. Yes my bore is mirror clean, and I have brushed to check for any leading etc.

What I will do, is carry out the slugging technique as prescribed by you Mr Nate and as you said, fire lap.

Whilst this is a little frustrating, I do enjoy working on my guns! Kinda exciting at the same time.

I will be switching to a Uberti 1873 rifle or carbine for western action, but really love the 92 for heavy duty loads. In terms of reliability, it is my go to rifle.

Thanks again for the superb advice.

[theozzman]

Regarding the lapping; can I use hand lapping in place of fire lapping? It would be more practical for me at this point as I could do it at home without going to the range. And as a friend mentioned in an above post, I could concentrate on the main tight spots first.

[Centennial]

I think Fire lap is better. It is worth the trip to the range. Plus you can clean it and shoot right after and see test results if any improvement on paper.