|
|
Post by jdre2155 on Apr 28, 2020 11:48:18 GMT -5
Howdy,
I have a recent production 629-6 that I am hoping to get some consensus on what my issue is. Not new to guns by a long shot, but as you know the bunny hole of firearms takes you from blissfully ignorant “hey I have a 44 magnum and it shoots 44 magnum ammunition” down as far into customizations, bullet dimensions, tolerances and adjustments as you wish to go. Understandable, the objective is a 100% functional and accurate sixgun and it takes work to get there.
That said, I have a 629. I started reloading a year ago for my 38’s and 45 colts, and on to making 44 specials for target fun in the 44 mag. What I’m noticing is leading is an issue at the start of the breech just past the forcing cone. It’s only in that breech section, the rest of the barrel looks great. Now thanks to all of you and reading about this stuff a little I tried my best to do my homework and came up with the following:
629-6 specs:
Slugged cylinders - .430 average
Cylinder observations - very consistent chambers, none seemed ‘tighter’ than the other as far as tapping a slug down. if I drop the slug I just forced through the same cylinder hole, it will still have friction slight enough that it would require a gentle tap from a hammer to pop through.... lead rebounding?
Slugged barrel - high (grooves) .428; low (lands) .423
Barrel observations - after slug made it completely into the muzzle, tapping was consistent and easy. Around the breech where the issue is occurring it did seem like there was some constriction there but I didn’t have to hammer away to get the slug through. Just took a little more tapping and it passed through. The measurements were the highest points (basically the edge of two grooves) and lowest (land and a groove) since the barrel has an odd number of lands in it.
Additional info - electronic calipers used (doesn't go past thousands unfortunately) and the slugs were pure lead fishing weights.
Bullet and load specs:
Bullet - HSM hardcast 240 grain SWC .430
Actual bullet diameter - .431 and consistent between 10 test samples
Powder - Unique
Powder load - 6 grains (reminder this is 44 special target ammo not mag)
Brass - Starline
Primer - Remington large Pistol (standard not magnum)
So that is about all I have so far. Guess my question to you all is does any of that strike you as being abnormal and potentially cause an issue especially with leading? My intuition says mess with the bullet and load before ever changing something on the gun. But maybe you see something I don’t.
Another observation, I did just recently pick up a Ruger 44 special bisley and between it and the 629 tried dropping an HSM .431 diameter bullet through each of the chambers. With the Ruger all chambers had extremely light friction that just required a slight nudge with a pen to pop out the front of the cylinder; the 629 was absolutely stuck with the same bullet that it would have taken tapping with a hammer to make it through the front of the cylinder.
Anyways, thank you for taking the time to read!
JDre
|
|
|
|
Post by 98redline on Apr 28, 2020 12:03:51 GMT -5
It seems like you have done your homework.
Given what you have done thus far I would tend to say you have a bit of thread choke where the barrel screws into the frame. This is what gives you that little extra push required to get the bullet past that section of the barrel.
With that I would say that a few rounds of fire lapping is what is in order for your gun. That should remove the thread choke and give you a mirror polished, slightly tapered bore, perfect for slinging hard cast loads. Even guns that are decent shooters normally benefit from some fire lapping so you can be relatively confident that you aren't going to do something that will mess up the gun.
On the Ruger side of things, all of my Ruger 44 mags like bullets sized .432. A .431 sized bullet will push through with just the slightest amount of resistance, a .432 fits with a decent push.
Trying to fire .430 sized bullets out of them always ends up with poor accuracy and/or barrel leading.
|
|
|
|
Post by Encore64 on Apr 28, 2020 12:19:07 GMT -5
That would be some mighty shallow rifling at .0025". That's about half of normal.
|
|
|
|
Post by bradshaw on Apr 28, 2020 12:31:27 GMT -5
“..." the objective is a 100% functional and accurate sixgun and it takes work to get there.
"Ruger 44 special bisley and between it and the 629 tried dropping an HSM .431 diameter bullet through each of the chambers. With the Ruger all chambers had extremely light friction that just required a slight nudge with a pen to pop out the front of the cylinder; the 629 was absolutely stuck with the same bullet that it would have taken tapping with a hammer to make it through the front of the cylinder.”
----JDr
*****
Dre.... you’ve made a god start. M-29 barrels which which I’m familiar are drop forged, machined, gun drilled, then rifled with a pull-through broach----a long tool of many teeth which progressively shave grooves until desired groove diameter is reached. Many of the older barrels were micro-honed after gun-drilling. Honed barrels show crosshatching on the lands. These barrels tend to phenomenal accuracy; some of my 29’s wear factory barrels I wouldn’t trade for any custom barrel. Non-honed barrels also may be exceedingly accurate----we’re talking 5x5 shots into 2-inches and less @ 100 yards.
Compression ring (thread choke)
You may have a fine barrel, screwed to the frame by Gorilla Monsoon, notable for gorilla arms and the mind of a cedar stump. When slugging the lightly oiled barrel, I index the pure lead egg sinker and tap int through with a taped brass rod. Steel is o.k. when properly taped. Once started, if you can push it through with hand pressure, do so. I re-dex the slug to the same lands and push through by hand. This second pass for sure reveals any loose or tight spots, either of which prevents pristine accuracy.
The COMPRESSION RING caper----a.k.a. thread choke----has been discussed with some regularity on Singleactions. My first choice remedy is to pull the barrel to properly time the threads. Once the barrel is pulled, you may find the compression ring gone. If thread choke disappears, turn BARREL SHOULDER until the barrel hand tightens to 10-12 o’clock BTDC (Before Top Dead Center). Most likely, the BARREL FACE is then trimmed just enough to allow free cylinder rotation double action. Check to be sure EJECTOR ROD does not hang on ejector rod latch (spring-loaded plunger on underside of barrel).
Chamber exit holes (throats)
A vernier, dial, or digital caliper is a imprecise tool for measuring exit holes. To be sure, you don’t want to hone before accurate measurement and, preferably, targeting. A hole micrometer or pin gauges are preferable.
Change gun, bullet, or load?
* Address compression ring first.
* Target @ minimum 25 yards; preferably 50 or 100 yards.
David Bradshaw
|
|
|
|
Post by jdre2155 on Apr 28, 2020 15:47:30 GMT -5
Thanks folks for the quick replies, Seems you are on the dot about the compression ring at the breech.... I re slugged the barrel and had to tamp it down lightly with a hammer and peened a mark into the top of the slug to note the groove it fit into and re ran the same slug a couple more times by hand. Sure enough a nice easy glide till I hit a wall at the breech.... that required tapping lightly with a hammer still to get it past. I do enjoy my own work and projects that are within my limitations, I looked up how to remove a S&W barrel and it screams send to a competent gunsmith! This thread seemed to have a rather good explanation in the first response to the OP: smith-wessonforum.com/s-w-smithing/183684-revolver-barrel-removal.htmlIf anyone knows of a decent Smith to do a job such as that please let me know. Between this ‘corona crud’ going around and potentially getting laid off I would be wise to wait till things calm down but never hurts to start getting a game plan together. Fire lapping seems pretty straightforward, however if the best option would be to remove and apply the barrel correctly the that is what needs to happen. As far as pin gauges, I see kits from $30 to $200 depending on range of hole sizes and incremental sizes. It appears from Carr Lane and others you can pick up individual pin gauges from Vermont Gauge. Any recommendations on this one? Seems you could pick up a set in range of the caliber rather than an entire set? Thanks again for the help! JDre |
|
|
|
Post by 98redline on Apr 29, 2020 7:51:08 GMT -5
Not to hijack the thread but maybe David could weigh in on this question.
I understand that removing the barrel, turning down the shoulder, then re-setting the B/C gap might be the most correct way to fix a compression ring but how would you compare that to firelapping the ring out?
I don't have the tools or the proper knowledge at my disposal to perform the machining work on the barrel, however I do have the reloading equipment to put together the required firelapping rounds. For the revolvers I have owned that exhibited evidence of thread choke the firelapping method has seemed to have addressed the issue however but I am curious if there is something I have been missing by just shooting the constriction out.
|
|
|
|
Post by bradshaw on Apr 29, 2020 8:36:41 GMT -5
Not to hijack the thread but maybe David could weigh in on this question. I understand that removing the barrel, turning down the shoulder, then re-setting the B/C gap might be the most correct way to fix a compression ring but how would you compare that to firelapping the ring out? I don't have the tools or the proper knowledge at my disposal to perform the machining work on the barrel, however I do have the reloading equipment to put together the required firelapping rounds. For the revolvers I have owned that exhibited evidence of thread choke the firelapping method has seemed to have addressed the issue however but I am curious if there is something I have been missing by just shooting the constriction out. ***** JDre.... sounds like you correctly slugged the bore. 98redline.... completely valid question. Since most revolver barrels will never be removed, fire lapping should remove the swelled ring juncture of frame & barrel shoulder. I, down the road and thousands of magnums later, you removed the barrel set it back (barrel face or forcing cone erosion), would the now properly-timed barrel have a slight “threat groove” where the thread choke had been? I don’t know the answer. We know this about fire lapping, that it takes time and patience and many bullets to do it right. Especially on stainless steel, which seems to require many more rounds than chrome-moly to hone out the raised ring. An example of impatience would be the use of every coarse compound as a shortcut. If the compression ring disappears when the barrel is removed from the frame.... and the shoulder is turned, so that the barrel hand tightens to 10-12 degrees BTDC, then the only thing left is to dress the barrel face for minimum cylinder gap. The person who turns the barrel shoulder must know the simple arithmetic to calculate metal removal to thread pitch.... to cut within a few thousandths. Provided the forcing cone is concentric & smooth, there should be no need to re-cut. The so-called average forcing cone is deep enough to easily accommodate setting back the barrel one thread. Hopefully, a barrel with a compression ring can be saved. The barrel must otherwise be uniform. Don’t expect a bore with loose or tight spots to be a shooter. In the old days it was standard practice for the handgun handloader to slug the bore. Casters especially. The practice is far from obsolete. David Bradshaw |
|
|
|
Post by 98redline on Apr 29, 2020 16:19:41 GMT -5
Not to hijack the thread but maybe David could weigh in on this question. I understand that removing the barrel, turning down the shoulder, then re-setting the B/C gap might be the most correct way to fix a compression ring but how would you compare that to firelapping the ring out? I don't have the tools or the proper knowledge at my disposal to perform the machining work on the barrel, however I do have the reloading equipment to put together the required firelapping rounds. For the revolvers I have owned that exhibited evidence of thread choke the firelapping method has seemed to have addressed the issue however but I am curious if there is something I have been missing by just shooting the constriction out. ***** JDre.... sounds like you correctly slugged the bore. 98redline.... completely valid question. Since most revolver barrels will never be removed, fire lapping should remove the swelled ring juncture of frame & barrel shoulder. I, down the road and thousands of magnums later, you removed the barrel set it back (barrel face or forcing cone erosion), would the now properly-timed barrel have a slight “threat groove” where the thread choke had been? I don’t know the answer. We know this about fire lapping, that it takes time and patience and many bullets to do it right. Especially on stainless steel, which seems to require many more rounds than chrome-moly to hone out the raised ring. An example of impatience would be the use of every coarse compound as a shortcut. If the compression ring disappears when the barrel is removed from the frame.... and the shoulder is turned, so that the barrel hand tightens to 10-12 degrees BTDC, then the only thing left is to dress the barrel face for minimum cylinder gap. The person who turns the barrel shoulder must know the simple arithmetic to calculate metal removal to thread pitch.... to cut within a few thousandths. Provided the forcing cone is concentric & smooth, there should be no need to re-cut. The so-called average forcing cone is deep enough to easily accommodate setting back the barrel one thread. Hopefully, a barrel with a compression ring can be saved. The barrel must otherwise be uniform. Don’t expect a bore with loose or tight spots to be a shooter. In the old days it was standard practice for the handgun handloader to slug the bore. Casters especially. The practice is far from obsolete. David Bradshaw That is an interesting perspective I had not previously considered. It would be a real stick in the eye to have custom work done on a previously firelapped gun only to have barrel leading return due to a big wallowed out ring in the forcing cone. I suspect it comes down to whether or not the deformation is plastic or elastic. The fact that your solution is to set back the shoulder to fix the issue would tend to support the elastic deformation theory and likely means that if the barrel is ever removed and set back that the bore might be adversely impacted. I suppose you could request the smith leave the shoulder a bit long then really wrench on the barrel, restoring the factory thread choke. |
|
|
|
Post by coltnewservice45 on May 22, 2020 13:12:59 GMT -5
A common factory method for mitigating "thread choke" without pulling the barrel is to use a round-hole broach 0.0005" less than minimum bore diameter, resembling a range-rod with carbide plug 4-5 times as long as its diameter, ground to a razor-edge on its front face. The barrel is swabbed with cutting oil and when the plug is inserted it will normally slide of its own weight to the point of thread constriction. With the cylinder and yoke assembly removed, the frame is held in a fixture and the carbide plug forced through the bore with an arbor press. Done correctly the tops of the lands at the choke are shaved to mirror finish and the constriction is gone. This, of course, does nothing in the grooves, but is a quick and inexpensive fix which is almost always satisfactory.
I watched a whole ten-board of S&W revolvers corrected by this method in about 20 minutes. One of them was mine and it still shoots great.
|
|
jgt
.327 Meteor
Enter your message here...
Posts: 782
|
Post by jgt on May 23, 2020 6:59:10 GMT -5
OR. you could drill a hole in the frame and mill a grove in the appropriate place on the barrel shank, then use a pin to hold the barrel once it is mated to the frame. It worked for eons until bean counters decided they knew the best way to build a revolver.
|
|
|
|
Post by jdre2155 on May 25, 2020 8:17:34 GMT -5
Thanks folks! Still reading up on all of this, I think I MIGHT (key word) have a solution. Not knowing or having a revolver smith, I saw on S&W’s website that they offer what they call an “Outdoor package large frame -N” for $200 through their performance center.
All of the features sound fine of what they do, but I feel like what would help is the part they say they will reset the barrel and cylinder gap. I feel like in order to do that (and put a crown muzzle on the barrel) they would need to pull the barrel. Which if I call in and explain my situation might solve my first issue.
Anyone ever send a revolver in for the performance center? Atleast it would be under warranty at S&W if they don’t resolve it?
Thanks again,
JDre
|
|
jgt
.327 Meteor
Enter your message here...
Posts: 782
|
Post by jgt on May 25, 2020 8:48:13 GMT -5
|
|
|
|
Post by jdre2155 on May 25, 2020 12:41:03 GMT -5
Ok, sorry I don’t have the ability, fixtures or drill press to do what you are describing. It would have been nice if they had stuck to the old ways but they didn’t, and one of the less evasive options provided to me for the torque fitted barrels they use now would be having the barrel removed and reset to the right torque and lose the compression ring (if I’m saying this right). That doesn’t work then I can try the fire lapping or something else more permanent. But the S&W performance center seems to offer a gunsmith package that would reset the barrel and slick up the rest of it at the same time so it seems like a good idea? If anyone has tried having work done by them I wouldn’t mind hearing about it. I don’t have a gunsmith that is good with a revolver so I’m out reading and looking at options. JDre |
|
|
|
Post by boolitdesigner on May 25, 2020 12:45:43 GMT -5
But the S&W performance center seems to offer a gunsmith package that would reset the barrel and slick up the rest of it at the same time so it seems like a good idea? Don't guess at what is included. Call the S&W performance center and tell them what you want and your concerns. See if they can do that or something close. |
|
|
|
Post by jdre2155 on May 26, 2020 12:51:40 GMT -5
Don't guess at what is included. Call the S&W performance center and tell them what you want and your concerns. See if they can do that or something close. Totally agree with that, I called them this morning and I guess they are not taking on paid work at this time but the CS rep felt I should send it in for a potential warranty issue and see if they can resolve it first. At least I can send a good descriptive letter along with it and maybe they can pull the barrel and reset it. I’ll note what happens when I hear back or get it back from them. Thanks again for all the help folks, appreciate the input! JDre |
|
