barrel constriction

[Oklahoma Rebel]

comparing the lipsey's ruger 480 SBH and their (ruger) SBH bisley 44 mag, has anyone noticed if one is more prone to the problem of barrel constriction than the other? and wouldn't using fire lapping make the end of the barrel too wide by the time the part of the barrel by the frame is good? fire lapping just scares me because it is irreversible. thanks,Travis

[C. Latch]

I'm no expert, but you rarely hear of a .44 ruger having frame choke; you commonly hear it about .45 caliber guns. I suspect that the .48 calibers would be even worse, but that's just a guess, not based in any experience.

On your second part, though, I can say this from experience:

Ruger's stainless pistol barrels are harder than a scorned woman's heart. By the time I got my .45 firelapped to the point that the frame choke was gone, I was ready to beat on it with rocks, or chisels. Fire lapping works on the throats (i.e. frame-choked area) but the lapping compound rapidly wears down to nothing, so that when you finish lapping away that frame choke, you may not even be able to tell that compound has ever touched the rest of your barrel. I can't. If you were closer I'd let you look at mine. Once you get an inch into my barrel, it still looks like the day it was new.

I don't think you could wear out the muzzle end of a ruger stainless barrel if you firelapped it with sandstone slugs over full charges of H110. They're just that hard.

[Good Cheer]

In the late 70's I lapped the frame constriction out of a Security Six with JB and a lot of TV time.
You could actually see the changes in hardness in the mirror polished barrel steel caused by the threading in.
Once polished and provided a custom mold from Richard Hoch it drove tacks happily ever after.

[nicholst55]

Fermin Garza (2Dogs on many forums) states that he has never seen revolver accuracy HARMED by firelapping. He is something of an authority on the subject, and I believe him.

Granted, anything can be done incorrectly if one tries hard enough, but I believe firelapping, properly performed, is normally beneficial to revolvers.

http://www.gunblast.com/FerminGarza-Firelapping.htm

[Bookworm]

I'm no expert, but you rarely hear of a .44 ruger having frame choke; you commonly hear it about .45 caliber guns. ....

I've got a rare one then. I have a 44Mag 5.5" Stainless SBH with frame choke.

I can feel it with a patched cleaning jag. I haven't done anything with it yet, beyond gathering the necessities for fire-lapping.

I have a few other Ruger 44 Mags to shoot, so I'll get to it when the spirit moves me.

[Rattlesnake Charlie]

You cannot harm the barrel by fire lapping. You can never get it larger than the bullet, actually slightly less. It is just the thing for the construction from the frame. I did it to my Ruger Super Blackhawk SS. Have did it t other handguns with barrel problems. Has always helped. Never hurt. Just as Verl Smith said.

[bosterr]

I was wondering, my S&W 44 has some thread choke too. I never owned a Colt revolver. Why doesn't my BFR .475 have any? If one company can make a gun without thread choke and varying sized throats, why can't the others? Another thing I think about... cylinder throats. Yes, I get it that Ruger reams 2 throats at a time and the reamers don't get changed at the same time. If they kept turning the cylinder so that both reamers make it the whole way around the cylinder, wouldn't they all come out the same? I was never a machinist or a gunsmith, but would it be hard to eliminate thread choke and throat issues? Sorry about the hi-jack.

[JSH]

This subject is like elbows, everyone has a couple.
Fermins, article is a good one. Read it before you proceed.
Think of this like "choke" in a shotgun. The smallest diameter should be at the muzzle.
If your cylinder is .355 and your bore is .357, look at some cylinder work before you lap.

Thread choke can be fixed without lapping. The barrel needs to be removed, shoulder moved one thread forward and then the forcing cone faced off. Don't quote me but I think it is 10 degrees before the front sight is at 12 o'clock. Yes the barrels will spring back to original or at least darn close to original ID. I have not heard of one not being an improvement.
I know of several SW barrels that were removed and then the front sight was set at 12 o'clock, the barrel had lock tite applied and allowed plenty of cute time. One 357 and a 44 I know of have been shot more than most guys here will shoot in a life time.

As as to one caliber being worse than another. Out of three 32's, zero choke. One 38 no, half a dozen 357's one had a small amount, one 41 has choke, 44 none, two 45's one has, two 480's one had.
From what I have run across in my few, it seems stainless may be more inclined to have choke, yet I own more stainless than blued. I actually like blued guns more, but maybe I have gotten lazy I don't have to worry near as much when packing them about putting any kind of marks in the finish.
Cylinders being under sized, now that is another story.
As mentioned read Fermins article, if you have questions ask. He is around here off and on, he is a busy man.
Jeff

[Oklahoma Rebel]

seems like the pattern is the larger the caliber the more likely to choke, good advice about getting your cylinders reamed if they need it before lapping, I can see that a too small cylinder would compress the boolit and lessen or negate the effects of lapping. I have another couple months before I can buy one, but I really like the 480 and the loads I have read about for it. would ruger fix the constriction or is that a lgs thing, if I didn't want to lap it but use the method JSH just mentioned? of course this is considering I end up with a problem gun, which I might not. just covering my bases

[JSH]

I would suggest a call to Ruger on the thread choke.
IMHO, they guns should not have left that way to begin with. So I opt to fix it on my dime.

Choke is not exclusive to Ruger, I have seen it and talked to folks ftf that have had it on every make and model,DA and SA.
SW was a pita to work with. Both new guns and neither would shoot into a bucket. Sent back, one was supposedly fixed as work order came back with it,my he other was sent back and said to be within specs. Both came back with choke. The one with the work order we suspect they just spun another barrel on and never checked it. Here is the kicker, it was a PC gun!!! Crazy.

I will give dougguy a nod for the cylinder work, and I still have not had him do any of mine yet! I got five for him to do,but getting the coin together to ship all of them at once, they are setting idle as I type
jeff

[Oklahoma Rebel]

thanks for the tips, hopefully it is a problem I will not have to deal with, but I probably will have dougguy ream all the cylinders for consistency and accuracy with cast boolits, they should be .0005 over groove diameter, right?

[DougGuy]

thanks for the tips, hopefully it is a problem I will not have to deal with, but I probably will have dougguy ream all the cylinders for consistency and accuracy with cast boolits, they should be .0005 over groove diameter, right?

Throats should be .0005" ~ .001" over boolit diameter. Boolit diameter should be .001" ~ .002" over groove diameter..

Waste of time contacting Ruger over thread choke. They know it exists but if they shoot 3 factory loads (14,000psi standard 45 Colt pressure) and it groups decently, they will send it back un-repaired. You (we) are on our own with thread choke. I -do- have a very rare 45 caliber Taylor throat reamer if the choke is severe this works.

[Oklahoma Rebel]

cant believe they don't even check all 5-6 shots!