Model 627 PC, bad forcing cone and throat?

[enC]

I purchased my first revolver a while back, a model 627 Performance center in .357 and I've had some issues that I'd like some advise on.

It started showing quite quickly when I was shooting some LWC 38sp and they started to tumble, that's when I noticed that there was a lot of lead in the barrel.

After cleaning and inspecting it I found that the forcing cone looked really rough and and seem to have done a bad chamfer cut of the rifling at the throat. As seen in the picture it has left a "lump" on the side of the chamfer of each rifling. And as seen the lead build up directly after the lumps also.

After contact with my store it was sent in for a check and the forcing cone was recut, but to me the issue is still there. It's possible to feel the lump at the start of the rifling.

What is you opinion, is this normal on the forcing cones?
Do you think my issue with excessive lead buildup could come from this issue so I should contact them again?

The barrel itself also have these traverse marks in the barrel but S&W insists that they are normal toolmarks from the new process and do not affect precision. But they do grab a lot of copper..

 

[tominboise]

I don't know about the weird v shape at the beginning of the lands. The transverse marks are reamer marks. Depending on the quality of the manufacturer and the rifling method used, they can been seen or not.

I have used the Tubbs final finish system in a couple of rifles with good results, to polish out some of the reamer marks and greatly reduce fouling. I don't know if they make a system for 357 mag but probably.

I can't help on the forcing cone / start of rifling issue, other than to say that it doesn't look right to me, nor have I ever seen marks like that.

 

[joebuck]

Maybe S&W has secretly moved production to China. It seems likely with all the garbage coming out of Springfield lately that appears on this forum. What a shame.

 

[Protocall_Design]

The forcing cone had problems that are not as bad now. You need to check for barrel constriction just ahead of the forcing cone. That will cause leading with lead bullets and poor groups with any bullets. You may want to fire lap the barrel to smooth everything out.

 

[Lou_the_welder]

What's interesting to me, is that , that is supposed to be an ECM cut barrel with machine marks(?).

I would send it back and complain about the accuracy and complain about the performance of the gun itself.

I can see the lines inside the rifling. Not good.

I had a 5" PC 627. It looked nothing like that. It shot ok. But ended up selling it because the R8 replaced it as the more accurate gun. (For me).

 

[Pizza Bob]

What's interesting to me, is that , that is supposed to be an ECM cut barrel with machine marks(?).

IIRC, PC guns did not use ECM rifling, They were/are still cut with a reamer or button.

Adios,

Pizza Bob

 

[Lou_the_welder]

IIRC, PC guns did not use ECM rifling, They were/are still cut with a reamer or button.



Adios,



Pizza Bob

The literature has always been confusing.
For example, I was in a thread where the 929 PC had shown it had a ecm cut barrel(from what was written), and later someone posted a video showing Jerry Miculek saying himself it was a broach cut barrel. (So , you might be right!)
So, its been confusing. Or what was written i believe was past a certain year , all of Smith and Wessons barrels had switched over to ecm.

Those tooling marks on the OP's barrel to me don't look normal in any way , and however they got there, I believe might affect the bullets performance in the barrel itself.

 

[StakeOut]

PC means performance center or poor control?

This is one of the reasons some revolver production has stopped and older models prices are surging.

 

[stansdds]

That is some poor machining!

If a barrel is not properly installed, basically not cutting back the shoulder so that the barrel achieves correct torque when tightened to the frame so that that the rib and front sight are properly aligned with the frame and rear sight, over tightening occurs. When this happens, the result is the portion of the barrel that is threaded into the frame will slightly bulge inwards, creating a constriction. When this happens, you will get poor accuracy and lead fouling in the barrel. The solution to this is to remove the barrel and adjust the barrel shoulder so that the barrel is not over torqued in order to get the proper rib and sight alignment.

 

[enC]

The forcing cone had problems that are not as bad now. You need to check for barrel constriction just ahead of the forcing cone. That will cause leading with lead bullets and poor groups with any bullets. You may want to fire lap the barrel to smooth everything out.

With constriction, do you mean in form of like foulings, or barrel diameter need to be measured then?

My issue with the forcing cone is that I still believe that the deformation to the start of the lands that goes in the to groves will catch lead on lead bullets and start fouling, at least it's my theory.

Since it's basically still a new gun, I don't want to make any interventions on my own at least yet. I'm a bit disappointed, it's not close to the finnish of my CZ75 for a third of the price, I expected better from a PC gun, so I hope they will be able to fix it.

/enC

 

[Jcon72]

Wow, are those "tooling" marks or did someone run a tap down your barrel to thread the inside of the muzzle?

 

[stansdds]

Since it is a new firearm, I'd contact S&W, let them know the issues, they might want to see the pics, they will likely send you a shipping label so you can send it back to be fixed.

 

[mtgianni]

10 years ago the answer would be to run 500-1500 jacketed bullets through it at max velocities to smooth things out. With the cost of today's components and availability that isn't easily done. Since it is a new gun I would be hesitant to lap it out but if the factory says it's fine you have few other recourse's.

 

[Protocall_Design]

With constriction, do you mean in form of like foulings, or barrel diameter need to be measured then?

My issue with the forcing cone is that I still believe that the deformation to the start of the lands that goes in the to groves will catch lead on lead bullets and start fouling, at least it's my theory.

Since it's basically still a new gun, I don't want to make any interventions on my own at least yet. I'm a bit disappointed, it's not close to the finnish of my CZ75 for a third of the price, I expected better from a PC gun, so I hope they will be able to fix it.

/enC

To check for constriction, you need to clean the barrel very well first. Then you need a set of gage pins. They are made in increments of .001. You find the largest one that will slide into the muzzle end of the rifling, and see if it goes all the way through. If it does, there is no constriction. If it stops before coming out the forcing cone end, then you try the next smaller gage pin, if it sticks, you try the next smaller, etc. the difference in size of pins that start in the muzzle and come out the back is the amount of constriction present. I think the forcing cone and the rest of the barrel is still not very good. I would send the gun back to S&W.

 

[oysterer]

no button has gone through this, thats for sure. I think these rings perpendicular to the barrel are EDM marks from the electro chemical barrel cutting. Try to make guns with the cheapest techniques and no QC and then leave it all rough/tumble for the customer to eat it or die. Embarrassing.

 

[Narragansett]

no button has gone through this, thats for sure. I think these rings perpendicular to the barrel are EDM marks from the electro chemical barrel cutting. Try to make guns with the cheapest techniques and no QC and then leave it all rough/tumble for the customer to eat it or die. Embarrassing.

Don't sugar coat it Mark, give it to em straight.

BTW, I agree on the QC issue