8shot
Member
Considering buying a S&W 986 (5") revolver and am wondering if barrel choke is as common in that 9mm revolver as it is in the 686 357 revolvers.
Barrel choke in S&W 986 (9mm) revolvers?
- Thread starter 8shot
- Start date
Register to hide this ad
Protocall_Design
Vendor
Any revolver may or may not have it, depending on the tolerance stack of that particular barrel and frame. You just have to measure whatever one you get, and find out.
I don't have either a 986 or a 686
I do have a set of pin gauges and lots of S&W revolver. I have checked quite a few by dropping the largest pin that would fit in the muzzle and so far only one has hung up. I have checked quite a few N frame 45s and K frame 357 as they are the main guns I rebarrel or fit cylinders to. Pin gauges check cylinder alignment better than range rods. If the tightest pin goes though the bore there can not be much choke
I do not believe that barrel choke is as common as many believe. First of all it is not all that easy to compress small bore tubes. Next, if bore choke was common, the K frame 38s and 357s would be far more apt to display it as they have thinner shanks than either N frame 45 or L frame 357. J frames would almost all have it.
N frame 45. .670-.452=.218/2=.109,
N frame 44. .670-.429=.241/2=.1205
L frame 357 .562..357=.205/2=.1025,
K frame 357 .540-.357=.183/2= .0915
J frame 38 .500-.357=.143/2=.0715
I do know lots of people have used both guns in completion.
People should actually shoot their guns before they start worrying about them having problems. 95% of revolvers will shoot better than 95% of shooters can shoot them. 5% of 5% isn't much. My Ransom rest proves this theory to me repeatably.
I do have a set of pin gauges and lots of S&W revolver. I have checked quite a few by dropping the largest pin that would fit in the muzzle and so far only one has hung up. I have checked quite a few N frame 45s and K frame 357 as they are the main guns I rebarrel or fit cylinders to. Pin gauges check cylinder alignment better than range rods. If the tightest pin goes though the bore there can not be much choke
I do not believe that barrel choke is as common as many believe. First of all it is not all that easy to compress small bore tubes. Next, if bore choke was common, the K frame 38s and 357s would be far more apt to display it as they have thinner shanks than either N frame 45 or L frame 357. J frames would almost all have it.
N frame 45. .670-.452=.218/2=.109,
N frame 44. .670-.429=.241/2=.1205
L frame 357 .562..357=.205/2=.1025,
K frame 357 .540-.357=.183/2= .0915
J frame 38 .500-.357=.143/2=.0715
I do know lots of people have used both guns in completion.
People should actually shoot their guns before they start worrying about them having problems. 95% of revolvers will shoot better than 95% of shooters can shoot them. 5% of 5% isn't much. My Ransom rest proves this theory to me repeatably.
Last edited:
OP
8shot
Member
I have had (3) brand new in the blue plastic box 686 revolvers with significant barrel choke within the last 12 months. Now I'm a little "gun shy" wanting to buy a 986.
How did you measure it and how did it effect the accuracy???
I believe you would need to use a lot of torque to time a barrel and get the bore to compress a significant amount. But, I will admit that I am not all that impressed with recent S&W workmanship.
I believe you would need to use a lot of torque to time a barrel and get the bore to compress a significant amount. But, I will admit that I am not all that impressed with recent S&W workmanship.
Last edited:
OP
8shot
Member
Have a standard Brownells range rod that I have owned for years, always use it to check cylinder alignment. Really didn't need a range rod, the rifling distortion and barrel twist "ring" was visible in front of the forcing cone.
With the help of Warren Moore (Protocall-Design) I made a barrel jig and R&R the barrels. They sprung back and accuracy with the 7" 686 revolvers is now outstanding. (1-1/2" 50yards double action rested).
BTW: Never shot them with the barrel choke condition.
Wonder if I can buy a new 986 without the barrel installed so I can install it myself.
Last edited:
I am really curious. Part of the reason I mess with revolvers.
It really don't take that much torque to have a barrel stay in place.
How tight were the barrels when you removed them? How much did you have to take off the shoulders so the barrels torqued up right when reinstalled? It has to happen from way over torquing the barrel to get it to time.
I do believe they can have choke, but it has to take some force to happen. I have had barrels tighten up early and said nope rather than apply more force, but I they were pretty tight at that point.
If you already have a set up, get one and if need be remove and reinstall the barrel.
A whole turn of a barrel is .02777 so 10 degrees is only takes about about .0008. A quarter turn (90 degrees) is right at .007
I als9o wonder how they would have shot prior to the R&R
It really don't take that much torque to have a barrel stay in place.
How tight were the barrels when you removed them? How much did you have to take off the shoulders so the barrels torqued up right when reinstalled? It has to happen from way over torquing the barrel to get it to time.
I do believe they can have choke, but it has to take some force to happen. I have had barrels tighten up early and said nope rather than apply more force, but I they were pretty tight at that point.
If you already have a set up, get one and if need be remove and reinstall the barrel.
A whole turn of a barrel is .02777 so 10 degrees is only takes about about .0008. A quarter turn (90 degrees) is right at .007
I als9o wonder how they would have shot prior to the R&R
Last edited:
With the thread relief cut in the non-pinned barrels, I've seen more barrels with distorted rifling and minor bore enlargement than swaged down areas. (The old pinned types seem more prone to constrictions as there's no thread relief cut.)
More common with the larger calibers in a particular frame.
Bore distress in a 9mm or .357 barrel in an N-Frame would the least likely.
Probably the most obvious example I have is in a .40 S&W L-Frame. Quite "jugged" but it shoots OK.
There's photos in older threads.
As noted above, either cull those with obvious dramas before purchase or just shoot 'em and observe the results.
More common with the larger calibers in a particular frame.
Bore distress in a 9mm or .357 barrel in an N-Frame would the least likely.
Probably the most obvious example I have is in a .40 S&W L-Frame. Quite "jugged" but it shoots OK.
There's photos in older threads.
As noted above, either cull those with obvious dramas before purchase or just shoot 'em and observe the results.
OP
8shot
Member
Will be sending PM with contact info
OP
8shot
Member
You are spot on because if you return a revolver for the obvious condition S&W will not address or even mention the condition. They'll make some other "repair" and send it back.
Protocall_Design
Vendor
I have had and fixed several choked barrels. it's not uncommon to find a .002 restriction in them, I've had a couple that were .003 smaller than the rest of the barrel. When they have .002 or more, they tend to lead up with lead bullets, and not shoot good groups (at 50 yds.) with any bullets. Shooting at 7 or 10 yards doesn't tell you much.
When you remove the barrel from the frame, it will spring back to original size. All you have to do then is face off the back so the front sight is about 1 o'clock looking from the back of the gun when hand tight. Bringing it on up to 12 o'clock will give you plenty of tightness without any choke. If you face off a little too much and it goes past 12 o'clock, put it on with blue Loctite, set it at 12, and let it sit undisturbed for a day. It will still work fine.
I have found that a very high percentage of factory barrels have good rifling, but poorly done ends. If the barrel doesn't shoot well, recutting the muzzle crown and forcing cone, and fixing choke if needed, will usually make it a match barrel with loads going over 900 FPS. The rifling twist is too slow to stabilize slower, light target loads out to 50 yds. That's the reason all the PPC guns had custom barrels with 1 in 10 to 1 in 14 twist. Those will stabilize bullets from 650 - 700 fps up through magnum velocities.
These have been my personal findings over many years. YMMV.
When you remove the barrel from the frame, it will spring back to original size. All you have to do then is face off the back so the front sight is about 1 o'clock looking from the back of the gun when hand tight. Bringing it on up to 12 o'clock will give you plenty of tightness without any choke. If you face off a little too much and it goes past 12 o'clock, put it on with blue Loctite, set it at 12, and let it sit undisturbed for a day. It will still work fine.
I have found that a very high percentage of factory barrels have good rifling, but poorly done ends. If the barrel doesn't shoot well, recutting the muzzle crown and forcing cone, and fixing choke if needed, will usually make it a match barrel with loads going over 900 FPS. The rifling twist is too slow to stabilize slower, light target loads out to 50 yds. That's the reason all the PPC guns had custom barrels with 1 in 10 to 1 in 14 twist. Those will stabilize bullets from 650 - 700 fps up through magnum velocities.
These have been my personal findings over many years. YMMV.
Last edited:
Jim Watson
Member
Learn something new every day, I never imagined the barrel would "spring back". I have heard a lot about thread choke but the remedy was usually fire lapping or maybe a Taylor throat.
Protocall_Design
Vendor
Fire lapping or Taylor throating works for those who don't want to remove the barrel. For me, taking the barrel off is the quickest, easiest fix. I have a lot of tools to work with, that most people don't have. Most gunsmiths have a frame wrench and lathe, though.
Last edited:
Don't have any 9mm revolvers to comment on but I have found over the years that two of my new revolvers, a M610-3 & a M625-8PC, had barrel constrictions at the barrel-frame union.
They were found using pin gages.
Both constrictions were in the .0010-.0015" range & I was able to hand-lap them out & now they're excellent shooters.
.
They were found using pin gages.
Both constrictions were in the .0010-.0015" range & I was able to hand-lap them out & now they're excellent shooters.
.
