Match vs standard chamber

[Idgunner]

I put a McGowen varmint barrel on my Savage .223 in May of 2015 and it is already 'shot out'. (big grin here) The barrel has been a real good shooter with ragged hole accuracy and cold barrel one shot hits on rock chucks 487 yards away. I've got about 2000 rounds down the tube.

Now that the lands are shot out another 1/10 of an inch from the original long throat I'm talking to my gunsmith about cutting off a thread or two and cutting a new chamber to get close to the lands again. McGowen tells me that the original chamber was cut with a standard PTG 223 reamer. The gun is used primarily for varmint hunting and the groups are opening up a bit and I can't reach the lands any longer due to magazine restrictions.

My question is whether there would be any advantage in going with a match reamer vs the standard reamer to cut the new chamber. I assume that if I did that I could well wind up pulling the bullets on all of the rounds I now have loaded to resize cases because they may not chamber. (I neck size only).

I recently built a case annealer to try to get consistent neck tension on my seated bullets and to help extend the life of the brass. It looks like the match chamber has slightly smaller dimensions than the standard chamber so I would think that expansion and contraction would also be reduced.

Let me know what you think. Thanks ahead of time.

 

[J E Custom]

Match chambers are no more than chambers with slightly different dimensions. If you reload, the quality of the sizing will make the chamber perform as good as a "Match chamber" if they are both cut buy a good reamer and smith.

Annealing will help with uniform neck tension and a good set of bushing dies will size them very precisely.

If you are thinking about a new chamber the 223 Wylde is a good all round chamber and the 223 AI will extend the brass life and add some velocity with the 40o shoulder.

Match reamers/chambers can be problematic unless you turn all the necks and understand the effects of such dimension changes.

A standard SAMME chamber is just as accurate if fed quality re loads.

Just my opinion

J E CUSTOM

 

[just country]

morning, very good answer. GBOT TUM

 

[Idgunner]

J E, it looks like I'm going to go back with the same chamber. McGowen tells me that they used a PTD standard 223 reamer. It was a great barrel so I'm going to go back with the same thing. Thanks!!

 

[Idgunner]

morning, very good answer. GBOT TUM

What is GBOT TUM??

 

[okie man]

2000 dont seem like a lot. i have close too 4000 through my cz and its still a tack driver

 

[Idgunner]

2000 dont seem like a lot. i have close too 4000 through my cz and its still a tack driver

All I know is that the groups are opening up and the measured distance to the lands is a full 1/10 inch further that two years ago. Due to magazine restrictions i can no longer load close to the lands. It was not expected because I don't load to max pressures. I care about accuracy rather than speed so I thought it would last longer.

 

[Geno1112]

Condition of chamber should not be the only consideartion.
i would not re-chamber if the bore is fire cracked.

 

[Idgunner]

We inspected the bore with a scope. It is beautiful.

 

[J E Custom]

All I know is that the groups are opening up and the measured distance to the lands is a full 1/10 inch further that two years ago. Due to magazine restrictions i can no longer load close to the lands. It was not expected because I don't load to max pressures. I care about accuracy rather than speed so I thought it would last longer.

I think that setting the shoulder back is a good way to bring the accuracy back in a good barrel. Rarely does a barrel get shot out in its entirety, and setting back freshens up the lead and throat.

2000 rounds of 223 doesn't sound like enough to wash out the barrel so I would take a close look at your loading and components also. Powders do change and if you have good chronograph records, A new comparison may be necessary. I have had to alter my loads because of batch changes in powder.

Also you might recondition your brass and sort in close weight batches and size only enough to chamber the round. (We often over size the brass,allowing it to lay in the chamber hurting accuracy. I have a 308 with over 23,000 rounds through it and it will still shoot 1/2 MOA with iron sites. The throat is very worn, but when I do a minimum sizing and prep the brass as described, it still amazes me that It shoots that well.

I shoot NRA high power matches with it for over 15 years and I hate to mess with it. (Sentimental I guess).

Anyway, its worth a try before you do any barrel work.

J E CUSTOM

 

[Adikted]

All I know is that the groups are opening up and the measured distance to the lands is a full 1/10 inch further that two years ago. Due to magazine restrictions i can no longer load close to the lands. It was not expected because I don't load to max pressures. I care about accuracy rather than speed so I thought it would last longer.

It is possible that the extra bullet jump has reduced chamber pressure enough to pull you out of your accuracy node, I would chrono it to see if it was appreciably slower and maybe try massaging the load a little (more powder) if you've got to set the barrel back every 2000 rounds it's going to be a money pit

 

[Rich Coyle]

2000 dont seem like a lot. i have close too 4000 through my cz and its still a tack driver

I thought the same thing. When my .223 started opening up at 2,100 rounds I told the 'smith the barrel was shot out. He suggested switching to a different scope. I did. Went right back to the .3's.

 

[Garycrow]

2000 rounds is not much for a .223, I'd look for the problem being elsewhere before I'd go messing with the barrel.

 

[jrock]

I had a smith tell me to check headspace if accuracy is degrading. Said that is the first sign of things going bad. I had to disagree with him in my mind. I don't see how headspace would or could change, but I'm not a smith. Just tossing this out there as it's what I've heard.