Rough chamber?

[shortgrass]

Repeatedly, we see posts like this one showing scarred-up brass from a 'new' chamber (sometimes factory, sometimes custom cut). There are some "Doozies" about, as this would never occur if the newly chambered barrel was 'test fired' ,and the fired brass examined, before sending it out the door! Some must not care if they've done a good job or not. Or, they are so overly confident they neglect to double check their work. I see it as only prudent to fire a couple, measure the case heads and give it a close "look-see".

 

[bigngreen]

My guess is that's chambered in a cnc machine, if you are running by hand you feel and hear that kinda mess before it gets any where near that. They certainly didn't even give the chamber a cursory glance let alone a good inspection which implies someone was just loading barrels in a machine.

 

[adam32+P]

My guess is that's chambered in a cnc machine, if you are running by hand you feel and hear that kinda mess before it gets any where near that. They certainly didn't even give the chamber a cursory glance let alone a good inspection which implies someone was just loading barrels in a machine.

Yup. Probably a pre-fit from a big name...I doubt pre-fits even get test fired?

 

[ntsqd]

I appreciate the thought, but should be well under max with my powder charge. I just tried 38 grains again with the same issue. Attached pic of case head.

I spoke with the barrel smith, he was very willing to take it back and clean it up. Offered some other suggestions as well to try.

I'm going to guess that this post by the OP removes a mass production cnc from the list of possibilities. No idea how it was chambered though.

 

[Elk Hunter 338]

My guess is that's chambered in a cnc machine, if you are running by hand you feel and hear that kinda mess before it gets any where near that. They certainly didn't even give the chamber a cursory glance let alone a good inspection which implies someone was just loading barrels in a machine.

But still, whether its a prefit, used up reamer, not cleaning the reamer out, hell maybe it was a Friday night and he wanted too see his kids and have dinner etc. etc. the list is long but,, it all comes down too how the smith chooses too handle the situation. And by the sounds of it, is willing too fix their mistake with out question,,,,, which in this game is FRICKEN HUGE!!

 

[FrogFire7]

Correct, prefit, but not sure his chambering method

 

[VinceMule]

Retracting the reamer while the barrel is still turning is a really bad way to go. The best smiths will polish or rough up the chamber, inspect with a borescope, and put a long stem indicator in the throat to check and see how much run out there is from the machining process. These guys Charge a minimum of $350 to chamber, and they are worth every penny of that money!

 

[RidgeTop]

Since when are primers NOT a sign of pressure ?


if you have pressure, figure out why or get a bigger gun.

 

[bigngreen]

Retracting the reamer while the barrel is still turning is a really bad way to go. The best smiths will polish or rough up the chamber, inspect with a borescope, and put a long stem indicator in the throat to check and see how much run out there is from the machining process. These guys Charge a minimum of $350 to chamber, and they are worth every penny of that money!

That completely depends on your set up. A cnc pretty much standard procedure to not stop the spindle till headspace check.
I always retract running at least a ways to give the reamer some room before stopping to flush, If I stop with it engaged I have to pull the reamer with the tailstock and it pops out it's cut so tight.

 

[FrogFire7]

Since when are primers NOT a sign of pressure ?


if you have pressure, figure out why or get a bigger gun.

I did say not a GREAT indicator of pressure.

By the time primers are flat, you are WAY over. There are better indicators than primer alone, plus primers can sometimes give false indicators, such as cratering being cause by excessive firing pin hole size, etc.

It's a legit question though.

 

[shortgrass]

I'd have to examine that reamer under magnification before I'd use it again. It appears the flutes got loaded-up with cuttings and that scarred the chamber,,,,, or the reamer was trash to begin with. I can't,,, I won't let a chamber job leave my shop without test firing first. Gotta' look at the throat with the bore scope, too. It's just good machining practice to check your work! Take nothing for granted, no matter how much experience you have!

 

[tobnpr]

Correct, prefit,

Prefit, for what action? Shouldered or nutted?

I always try to test fire- but if I don't have the stock/chassis from the customer (or one of my own to fit the receiver and barrel inlet)- not to mention the ammunition, which isn't a given these days- it may not happen. Absent that, every barrel gets scoped anyway- and I'd certainly see the corresponding artifacts in the chamber.

Smith shoulda caught this, but at least he'll get it straightened out for ya. Far easier to scope these before removing them from the lathe setup to catch any problems- for me, it's more of a PITA to dial a completed chamber back in than it is new blank.

 

[FrogFire7]

Savage prefit without shoulder. Yeah the Smith was great to talk with, I'm sure stuff happens from time to time with any of them.