Need to be reamed

[Sharadeth]

My revolver that is! My GP-100 just doesn't want to close up the groups. Several hand loads later and I'm still looking at 3 to 4 inch groups at 7 yards (benched) with some leading and apparently this is pretty common. I have tried a few different sized bullets and none seem to do much.

So now I am looking to ream the cylinder throats to .358 and cut the forcing cone to 11 degrees. Seems to be the common recommendation for .357 revolvers that are shooting mostly lead. So now I need to find a way to get it done. Any body here do it, willing to lend the tools, or knows a good smith? I tried looking up cylinder smith but that website doesn't seem to work anymore. Any help would be appreciated

P.S. the most recent loads were dardas .358 180gr LRNFP over 13.3gr of IMR4227 at a ~1.58" OAL and a pretty hefty crimp.

 

[Traveler]

All three of the GP-100s I owned were spot on. Had to sell each one when money got tight.

You have anyone else shoot it yet?

 

[Sharadeth]

All three of the GP-100s I owned were spot on. Had to sell each one when money got tight.

You have anyone else shoot it yet?

Honestly mine does great with jacketed ammo but that just isn't something I'm to reload. I don't got that type of money

And yes, I've had a few other at the range shoot at different times, checking myself was the first step

 

[Sundazes]

I was going to recommend a good proctologist.. I gotta stop reading the titles and making assumptions.

 

[inkd]

My revolver that is! My GP-100 just doesn't want to close up the groups. Several hand loads later and I'm still looking at 3 to 4 inch groups at 7 yards (benched) with some leading and apparently this is pretty common. I have tried a few different sized bullets and none seem to do much.

So now I am looking to ream the cylinder throats to .358 and cut the forcing cone to 11 degrees. Seems to be the common recommendation for .357 revolvers that are shooting mostly lead. So now I need to find a way to get it done. Any body here do it, willing to lend the tools, or knows a good smith? I tried looking up cylinder smith but that website doesn't seem to work anymore. Any help would be appreciated

P.S. the most recent loads were dardas .358 180gr LRNFP over 13.3gr of IMR4227 at a ~1.58" OAL and a pretty hefty crimp.

Have you had the throats measured to see what they are at?

I've cut the forcing cones on a few Smith and Wesson revolvers, it'd be the same on a GP-100. Manson makes the best cutting tool but it's expensive for a one time job.

 

[Bikebreath]

Are you loading up .38 Specials? I had issues with my SP-101 with lead bullets in .38 hitting the forcing cone, deforming and giving poor groups. I just put the .38 load in .357 cases with better results.

 

[Sharadeth]

Are you loading up .38 Specials? I had issues with my SP-101 with lead bullets in .38 hitting the forcing cone, deforming and giving poor groups. I just put the .38 load in .357 cases with better results.

Loading in 357 starline brass. I'm not sure if I could put that load in 38 brass (with out other other probles at least)

 

[Bikebreath]

Loading in 357 starline brass. I'm not sure if I could put that load in 38 brass (with out other other probles at least)

No, sounds like a load not meant for .38 Special. I was just taking a stab to help solve the problem. Good luck, though.

 

[Sharadeth]

No, sounds like a load not meant for .38 Special. I was just taking a stab to help solve the problem. Good luck, though.

I do appreciate the look out though. Never know when I'll miss something pretty basic, I've been to do worse

 

[Traveler]

Honestly mine does great with jacketed ammo but that just isn't something I'm to reload. I don't got that type of money

And yes, I've had a few other at the range shoot at different times, checking myself was the first step

Plated like Berry's or X-treme are not much more than lead. The HP work very well in my 9mm and 45 ACP. Very accurate too.

 

[Sharadeth]

Have you had the throats measured to see what they are at?

I've cut the forcing cones on a few Smith and Wesson revolvers, it'd be the same on a GP-100. Manson makes the best cutting tool but it's expensive for a one time job.

My throats came out to about .3565. Barrel I'm not entirely sure, haven't been brave enough to slug it due to the 5 groves.

 

[Boom Boom]

So now I am looking to ream the cylinder throats to .358 and cut the forcing cone to 11 degrees. Seems to be the common recommendation for .357 revolvers that are shooting mostly lead.

Assuming the hand loads are quality work, you shouldn't have to do that for good accuracy at 7 yards with a GP-100. Send the gun back to Ruger first. Could be any number of things or a combo: cylinder timing is slightly off causing cone shaving, bad cylinder machining, excessive cylinder endshake, too little cylinder side-to-side play (yes, too little), bad barrel. Ruger will pay shipping both ways, diagnose and repair/replace the gun, and have it back to you in two or three weeks. No cost to you.

 

[inkd]

My throats came out to about .3565. Barrel I'm not entirely sure, haven't been brave enough to slug it due to the 5 groves.

If you can slug the barrel and measure the slug you could possible find a distributor of bullets that size close to your diameter. I believe Donnie Miculek, Jerry Miculek's brother, of Bayou Bullets will size to whatever diameter you want.

Finding ammo to match the gun may be a cheaper route than trying to get the cylinders and forcing cone done. Problem is that anyone I would trust to recommend you to is backed up more than several months.

When you are saying you are getting leading, do you mean it's shaving lead on the barrel extension or you are getting leading in the barrel from the bullets?

Lead shaving, or spitting, could be caused by the cylinder not perfectly aligned with the barrel, which can be caused by a number of things such as the gun being out of time or if it's used, the original owner may have liked to play movie start and whip the cylinder shut which will egg out the area where the ejector rod locks up in the frame.

Where are you at in Southern Maryland?

 

[Sharadeth]

Assuming the hand loads are quality work, you shouldn't have to do that for good accuracy at 7 yards with a GP-100. Send the gun back to Ruger first. Could be any number of things or a combo: cylinder timing is slightly off causing cone shaving, bad cylinder machining, excessive cylinder endshake, too little cylinder side-to-side play (yes, too little), bad barrel. Ruger will pay shipping both ways, diagnose and repair/replace the gun, and have it back to you in two or three weeks. No cost to you.

That is an option I will keep in mind. It could be, albeit unlikely, thread pinching I guess? Only way for me to tell is slug the barrel and see if it gets tighter there.

If you can slug the barrel and measure the slug you could possible find a distributor of bullets that size close to your diameter. I believe Donnie Miculek, Jerry Miculek's brother, of Bayou Bullets will size to whatever diameter you want.

Finding ammo to match the gun may be a cheaper route than trying to get the cylinders and forcing cone done. Problem is that anyone I would trust to recommend you to is backed up more than several months.

When you are saying you are getting leading, do you mean it's shaving lead on the barrel extension or you are getting leading in the barrel from the bullets?

Lead shaving, or spitting, could be caused by the cylinder not perfectly aligned with the barrel, which can be caused by a number of things such as the gun being out of time or if it's used, the original owner may have liked to play movie start and whip the cylinder shut which will egg out the area where the ejector rod locks up in the frame.

Where are you at in Southern Maryland?

The leading is near the muzzel. Forcing cone and cylinder faces are pretty clean. It's more of streaks than anything, but it is relatively minor, nothing a few brush passes won't fix.

As far as cylinder timing, end shake, and other factors of that sort, I'll admit that I'm not entirely sure how to tell how much is too much/ too little. I can definitely look into it though.

 

[inkd]

That is an option I will keep in mind. It could be, albeit unlikely, thread pinching I guess? Only way for me to tell is slug the barrel and see if it gets tighter there.



The leading is near the muzzel. Forcing cone and cylinder faces are pretty clean. It's more of streaks than anything, but it is relatively minor, nothing a few brush passes won't fix.

As far as cylinder timing, end shake, and other factors of that sort, I'll admit that I'm not entirely sure how to tell how much is too much/ too little. I can definitely look into it though.

Odds are if the only signs of lead are at the muzzle then the cylinder alignment is good. I'm not overly sure on Rugers but on Smiths it is possible to torque the barrel to the point where the extension actually compresses. It's not common but it can happen, mainly if someone had swapped barrels and didn't set it back correctly.

I'd have to check my notes and see if I have the information for the cylinder throats but those numbers look like what they should be for a .357 revolver.

What other weight and sized bullets have you tried in it?

Depending on where you are at in SOMD, when I get back in town I would be willing to check it out for you to look at alignment, endshake and such.

I am thinking your problem is going to be ammo related though. One think you can do is check the crown at the barrel. I am not sure if a buggered up crown would make a difference at 7 yards or not though, but a messed up crown would affect accuracy. It should be a smooth even cut all the way around with no nicks or burrs.

 

[Sharadeth]

Odds are if the only signs of lead are at the muzzle then the cylinder alignment is good. I'm not overly sure on Rugers but on Smiths it is possible to torque the barrel to the point where the extension actually compresses. It's not common but it can happen, mainly if someone had swapped barrels and didn't set it back correctly.

I'd have to check my notes and see if I have the information for the cylinder throats but those numbers look like what they should be for a .357 revolver.

What other weight and sized bullets have you tried in it?

Depending on where you are at in SOMD, when I get back in town I would be willing to check it out for you to look at alignment, endshake and such.

I am thinking your problem is going to be ammo related though. One think you can do is check the crown at the barrel. I am not sure if a buggered up crown would make a difference at 7 yards or not though, but a messed up crown would affect accuracy. It should be a smooth even cut all the way around with no nicks or burrs.

I think I may end up putting a wax slug down my barrel to check for thread choking. It it is there it will definitely ship it back to Ruger.

I'm going to look around tonight for a feeler gauge to check my end shake since it seems pretty easy to measure.

As far as other size and weights it's been 158gr lswc in .356, .357, and .358. They didn't lead due to the hi tek coating but all had about the same accuracy, maybe the .356 being a little less than the other two sizes. That's why I was thinking it was the cylinder throats. .3565 just seems a little small to me, especially if my bore is bigger than that.

My crown looks fine except a tiny bit of lead I need to get off of there. All my ammo has shot great out of other fire arms, even a Taurus 66 which I shot a 2.5" group at 25 yards off bench. Not sure about leading in the taurus though (it's not mine), but my rossi loves the rounds.

And I forgot to mention, I'm in the hughesville area about 4 miles out from the Harley dealership.

 

[Traveler]

Assuming the hand loads are quality work, you shouldn't have to do that for good accuracy at 7 yards with a GP-100. Send the gun back to Ruger first. Could be any number of things or a combo: cylinder timing is slightly off causing cone shaving, bad cylinder machining, excessive cylinder endshake, too little cylinder side-to-side play (yes, too little), bad barrel. Ruger will pay shipping both ways, diagnose and repair/replace the gun, and have it back to you in two or three weeks. No cost to you.

This ^^^

Ruger has excellent customer service.

 

[inkd]

I think I may end up putting a wax slug down my barrel to check for thread choking. It it is there it will definitely ship it back to Ruger.

I'm going to look around tonight for a feeler gauge to check my end shake since it seems pretty easy to measure.

As far as other size and weights it's been 158gr lswc in .356, .357, and .358. They didn't lead due to the hi tek coating but all had about the same accuracy, maybe the .356 being a little less than the other two sizes. That's why I was thinking it was the cylinder throats. .3565 just seems a little small to me, especially if my bore is bigger than that.

My crown looks fine except a tiny bit of lead I need to get off of there. All my ammo has shot great out of other fire arms, even a Taurus 66 which I shot a 2.5" group at 25 yards off bench. Not sure about leading in the taurus though (it's not mine), but my rossi loves the rounds.

And I forgot to mention, I'm in the hughesville area about 4 miles out from the Harley dealership.

When you say there is a tiny bit of lead you need to get off of the crown, is it on the outside of the crown and can you run a thumbnail over it and feel a drag?

When you clean, do you run a patch or use a brush and mop? I am wondering if there is a little nick on the inside of the crown? Run a Q-tip around the inside of the muzzle and see if it snags.

If everything looks good, a trip back to Ruger may be in order.

It seems as though you have used a variety of weights and sizes all with the same poor results. Only thing I can think that they all have in common is that they have to come out of the muzzle. That's the last thing every bullet touches as it goes downrange. It wouldn't matter if you had perfect throats and forcing cone, custom bullets made to fit the exact diameter of your gun. If it's tripping over a messed up crown at the muzzle, you are going to have accuracy issues.

 

[Sharadeth]

When you say there is a tiny bit of lead you need to get off of the crown, is it on the outside of the crown and can you run a thumbnail over it and feel a drag?

When you clean, do you run a patch or use a brush and mop? I am wondering if there is a little nick on the inside of the crown? Run a Q-tip around the inside of the muzzle and see if it snags.

If everything looks good, a trip back to Ruger may be in order.

It seems as though you have used a variety of weights and sizes all with the same poor results. Only thing I can think that they all have in common is that they have to come out of the muzzle. That's the last thing every bullet touches as it goes downrange. It wouldn't matter if you had perfect throats and forcing cone, custom bullets made to fit the exact diameter of your gun. If it's tripping over a messed up crown at the muzzle, you are going to have accuracy issues.

Well the crown is about as smooth as can be after cleaning. The B/C gap came in at .005 with the cylinder pushed foward and .008 pushed back, which seems to be in spec. I think a trip to ruger going to be my way to go since I have nothing to loose except some time.

I wish I still had some of my targets though. I had three 5 shot groups fired on the same day that had almost exactly the same pattern. Each one was only 1 shot different than the others and even the center to center measurements were damn close to each other. Strangest thing to me, but still large group sizes go figure

 

[inkd]

Well the crown is about as smooth as can be after cleaning. The B/C gap came in at .005 with the cylinder pushed foward and .008 pushed back, which seems to be in spec. I think a trip to ruger going to be my way to go since I have nothing to loose except some time.

I wish I still had some of my targets though. I had three 5 shot groups fired on the same day that had almost exactly the same pattern. Each one was only 1 shot different than the others and even the center to center measurements were damn close to each other. Strangest thing to me, but still large group sizes go figure

Well, I'm out of ideas, LOL!!!! Sounds like a trip back to the shop.