Shot the Cooper 260

S

stubblejumper

CGN Ultra frequent flyer
Rating - 100%
69   0   0
Location
Camrose
I finally got to shoot the Cooper 260 this weekend, and it looks promising. The groups are averaging sub 1/2", but there is some vertical stringing. I intend to try working with the seating depth, in an attempt to reduce the vertical stringing.

260cooper.jpg


260groups.jpg
 
Looks good, I like the 123gr Scenars. If the load includes a Federal primer, try exchanging it for a Winchester. I have had that small of an amount of stringing disappear moving to the hotter WLR. But pressures usually rise a bit as well.
Nice rifle, good luck.
 
It's a Federal 210 behind a compressed load of N560. I am going to seat them a little closer to the lands, as well as try some R-19. If neither of those work, I might try a hotter primer with a little less powder.
 
I tried the 142gr Matchking today, as well as the 120gr Ballistic Tip. Using H-4350, the Ballistic Tip averaged 5/8" for five shots, and ten 142gr Matchkings went into .590". The ten shot group was fired five shots, then let the barrel cool, then fire the second five shots.
 
Last edited:
That's it, load development is finished. I chronographed the load, then had eight rounds left, so I shot a five shot group, then a three shot group.The last two groups fired with the load that I settled on are below. The accuracy guarantee is three shots into 1/2", and that is just too easy with this rifle and load.

260load.jpg
 
Nice looking rig. I didn`t know a 1:9 twist would shoot 142's so well. What power ziess are you running on there?
 
Last edited:
Very nice, have you tried it over a chrony yet? It would be nice to see a 2800fps reading out of that load with that barrel length. It would make a great speed goat rig.....
 
The rifle wears a Conquest 4.5-14x44 with the Rapid Z 800 reticle. This morning the load averaged 2760fps in 17 degree temperatures, with a maximum variation of 11fps for five shots. I previously worked the load up to 43 grains, but I started to see some very slight pressure signs with a couple of rounds,and the groups began to open up slightly, so I backed it down to 42 grains. I shot two five shot groups at 200 yards that measured right around 1", during my last shooting session, but I have yet to shoot it farther. When I receive the bullets that are in the mail, I will shoot the gun to 500 yards to see how close the point of impact is to the reticle markings.
 
One thing that really stands out, is the thought that goes into the throating of Cooper rifles. In most cases, I can seat bullets to the lands, and the cartridges still fit the magazine. I find that a great asset in achieving great accuracy. Sako and Tikka could learn a lot from Cooper in that respect.
 
You must log in or register to reply here.
Back
Top Bottom