Will 0.01mm make a difference?

N

nate_g_2003

New member
I'm looking into buying a K31, just waiting on my 03 C&R (just mailed Monday!). When it come to bore size, I know smaller usually means better. In this case, I'm looking at two rifles, one with a 7.53 muzzle, and one with a 7.54 muzzle. Is the 7.53 necessarily going to be a better shooter than the 7.54, or give me (and my kids) a better/longer barrel life? Or am I just splitting a frog hair four ways at that difference?

Thanks y'all.
 
I think it should be one consideration, especially given that "new" would have been 7.51, and max the Swiss would accept as 7.56 from what I've read.
Both are well within spec.

Given that, bore and muzzle condition (as well as the overall condition of the rifle) should be given more weight, IMO. How sharp are the lands? Any nicks or gouges on the crown, etc..
 
also another consideration... you'll likely be reloading 308 ammo which is slightly oversized anyway. the larger bore would llikely perform better with reloads but factory gp11 would likely perform better from the smaller diameter.
 
I hadn't considered reloading, as I'm not setup for it (yet). A few things I've just come across say that .308s will work in that aspect, and my reading/math tells me that 7.5x55 GP11 actually runs at 7.77mm/.306".

This has me slightly worried, because everything I've ever read or experienced tells me I should get the 7.53 over the 7.54. But I'm now confused as to how there could even be a 0.2mm difference. Maybe one (7.77) is a groove measurement, and the 7.5x is the lands measurement?
 
Too much reading and math, folks, and too little measuring. 7.5 Swiss bullets actually run .3080-3085".

Ordinary .308 bullets for .30-'06, .308 Winchester, etc. will work fine.

Jim
 
"...7.5 Swiss bullets actually..." Yep. And neither it nor 7.62NATO mathematically convert from .308" to either metric designation. .308" converts to 7.82mm. So it shouldn't read 7.5 anything.
Buy the rifle that is in the best overall condition and don't worry about a thou. Or the metrics.
 
So since when do cartridge names make sense? FWIW, 7.62mm is .300", which is the bore diameter; bullet and groove diameter is .308". The .30-'06 and .30-30 are named from the bore diameter; .308 is named from the groove diameter. Same bullet size.

Jim
 
7.53mm vs 7.54mm, you must be measuring the bore, not the groove. You measured with calipers? Those things easier have tolerance of +/- 0.001". 0.01mm is 0.0004". Forget it. They are the same.

Cartridge names always do make sense, their own sense. They distinguish one cartridge from another, do they not?

-TL
 
Sure they make sense. Sort of. I once saw a gun shop clerk sell .303 Savage ammo to a guy who had a Rifle No. 4 Mk1* made by Savage. Well, the rifle was .303 and it was made by Savage, so he was right, right? :rolleyes:

Jim
 
tangolima: I'm not doing the actual measuring, Simpsons LTD is! :D

I didn't figure the 0.01mm would really matter all that much in the grand scheme of things. I have my eye on a few, with one in particular being my favorite of the lot. Waiting to get my 03 C&R in the mail before I purchase it. My gut keeps telling me to put the $$ down on it via layaway and wait until my 03 comes in, so I don't miss out on it.

Thanks everyone for the great info.
 
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