First Tight Chamber

TXGunNut · June 19, 2010, 10:29 PM

New Super Grade Model 70 seems to have a chamber a bit on the tight side, but within specs. Have noticed a few things. First: pressure seems to be a bit high with less-than-max loads. Only pressure signs are primers a bit flattened (Federal 210's) and bolt lift a bit hard @ times. Second: cases grow more than I'm used to. Trimmed them three firings ago and happened to notice that the cases were well over maximum length. I'm not a big fan of trimming cases, BTW.
I realize that all rifles are individuals but was wondering if these circumstances are related. Also understand that rifles like this are why we work our way up towards max loads instead of starting there. Is there any other characteristic of a tight chamber that I should be aware of?

Blue · June 19, 2010, 11:36 PM

http://www.brownells.com/.aspx/pid=1...ANING_COMPOUND

Polished chamber with this - fixed my problem. Maybe it will for you.

Chucked it up in drill with .45" cleaning swab. Your swab size might differ.

Coated and polished with swab and JB bore paste 3 or 4 times - then thoroughly cleaned.

Worked.

June 19, 2010, 10:29 PM	#1
TXGunNut Senior Member Join Date: January 16, 2010 Location: If you have to ask... Posts: 2,860	First Tight Chamber New Super Grade Model 70 seems to have a chamber a bit on the tight side, but within specs. Have noticed a few things. First: pressure seems to be a bit high with less-than-max loads. Only pressure signs are primers a bit flattened (Federal 210's) and bolt lift a bit hard @ times. Second: cases grow more than I'm used to. Trimmed them three firings ago and happened to notice that the cases were well over maximum length. I'm not a big fan of trimming cases, BTW. I realize that all rifles are individuals but was wondering if these circumstances are related. Also understand that rifles like this are why we work our way up towards max loads instead of starting there. Is there any other characteristic of a tight chamber that I should be aware of? __________________ Life Member NRA, TSRA Smokeless powder is a passing fad! -Steve Garbe I hate rude behavior in a man. I won't tolerate it. -Woodrow F. Call Lonesome Dove My favorite recipes start out with a handful of used wheelweights.

June 19, 2010, 11:36 PM	#2
Blue Senior Member Join Date: June 6, 2009 Posts: 113	This worked for me http://www.brownells.com/.aspx/pid=1...ANING_COMPOUND Polished chamber with this - fixed my problem. Maybe it will for you. Chucked it up in drill with .45" cleaning swab. Your swab size might differ. Coated and polished with swab and JB bore paste 3 or 4 times - then thoroughly cleaned. Worked.