Cooper Model 21 Chamber

[Travelor]

I have what I believe to be a early Model 21 (SN is two letters followed by 2 numbers) chambered in 204 Ruger. The fired cases, both factory and reloaded, show a pronounced expansion (.005" greater than a case fired by a Remington 700 in same caliber with ammo from the same box of ammo) at the "pressure ring" or just about 1/2" from the rear of the case.

Anyone notice this in their Cooper? If so what if anything have you done about it?

Thanks,
George

[17VLD]

.204 Ruger chamber it has to be at least a 2004,so not really an early model.
My Cooper .22PPC shoots very well but also has a big chamber.Sometimes
if a reamer is run in too fast the chamber will be oversize,most likely the reamer
is just speced too big to allow for more tolerance and clearence during field use.
Coopers really shoot well,look at Rick in Oregon's 20VT:)
You could call and see what they will do for you,how does it shoot?Also the serial# being short like yours really doesn't have to do with age like most guns,they can be somewhat random.Have fun with yours it is an awesome cartridge.:)
Matt

[hemiallen]

.
Coopers really shoot well,look at Rick in Oregon's 20VT:)

Matt

Thinking out loud... when I meet up with Rick, soon, I should give him my rifles and let him sort them out, the one's that don't shoot as well as Rick's, although having him shoot them may tell me what the problem is, lol.

He sure does know how to make the best of a rifle....

I may have to bring up reloading supplies, dies and the guns, heck a trip to Bend later this year would be a nice vacation trip to get the "tuned up" rifles back.

And Pilot Butte has great food, great Breweries and great friends....

Hmmmm.....:p

Allen

[TinMan]

What are first two letters in the S/N? That could help determine whether the rifle has been re-barreled, even if Cooper did it.

I believe these S/N are correct:

VA = 223
VE = 221FB
VF = 17 Rem
VG = 17Mk4
VK = 17HeeBee
VL = 17 Ackley Hornet
VR = 22 Hornet

[Travelor]

My "problem" Cooper has a serial number beginning with VP

[Herb in Pa]

My Cooper Varminter in 223 has a TGS prefix
Montana Varminter in 17 Fireball has a CF prefix

[Gabe221]

I have a model 22 that is in 22BR. It has a 1.690 chamber for a 1.520 cartridge, figure that out. It also has a bur where the reamer was removed. I don't have to worry about trimming brass for sure, and can't complain about the way it shoots. My serial # starts with a CF. All custom shop made (VARTAC).... Can't complain though, it shoots.