22 February 2010, 18:15
icemanls2.300 win mag after 15 shots opened up like a softball
I put a new VARI-X III scope on my .300 Win Mag yesterday and went out to shoot. I lapped the rings and bore sighted it and was 4 inches high and 3 inches right on first shot. This is a new rifle with about 5 rounds through it. After 5 shots i am in the bull, I change my target at 100 yds and fire a 5 shot group that is sub 1" with 150grain Remington Core-Lokts factory ammo. I walk down and change target and shoot another 5 for 15 of the box and it is tighter than the first. I'm thinking spectacular for factory ammo! I go change my target again and shoot the last 5 and the group opened up to 4" plus softball size and is a round circle pattern! I did not clean barrel during this 20 rounds and consisted of approx 30-40 min. Barrel was pretty warm after last 5. Could this be fouling? When i mounted scope i put a fine pencil mark at front and back of rings on scope and on dovetails front and back of mounts so i could see at a glance if anything moved and that is fine. Also after last group i slid a dollar bill along barrel to see if i had pressure anywhere and that was fine as well. This drove me crazy last night!
22 February 2010, 18:29
wasbeemanCould be fouling. Especially in a new rifle. Clean it up good and try again.
FYI, it ain't gonna take many boxes of that store bought ammo to equal a nice entry level reloading kit.

22 February 2010, 18:31
icemanls2I have all the stuff and do reload, I have (er had) 2 boxes of core-lokts(now 1 box left) i was shooting up for the brass.
22 February 2010, 18:42
jeffeossoscope mount is loose.. likely bases
22 February 2010, 19:18
icemanls2Nope, checked em. Rings and bases are tight.
22 February 2010, 19:20
BECooleBum scope?
Check with a collimator.
Maybe loose bedding screw?
22 February 2010, 19:25
icemanls2I suppose thats possible. Just because it's new don't mean it's good i suppose. Whats the best way to check for that if it gets knocked off every shot? Given that the first 15 shots were spot on and the last 5 went all over i sure won't rule that out. Didn't think of that. If i put my boresighter back in and it's way off i should be able to see if somthing's a miss shouldn't i?
23 February 2010, 00:48
plainsman456I would clean it and try again.
23 February 2010, 00:53
BECooleYeah, you are going to have to get a base-line with the collimator, shoot it until you get wide shots, then check it again.
23 February 2010, 07:54
IanDDid you let the barrel cool completely between strings?
23 February 2010, 15:16
Ingvar J. KristjanssonDon’t worry about it...the same happens to my Sako 300wm...nothing unusual...It only need good gleaning. After every 10-15 shots you must clean the barrel well to keep the group sub 1”.
My buddy shots a Sako TRG in 300wm and he is shooting some incredible groups at up 500 metres and he cleans the barrel every 10 shots to keep a good accuracy .
27 February 2010, 08:02
icemanls2Still trying to get back out, It snowed like the dickens all day today. I'm hoping to shoot a box tomarrow.
27 February 2010, 08:53
Dago Redoff topic but I'll tell you I often, with standard cartridges, bought loaded ammo and fired it to save the brass. if it wasn't a big difference in cost over buying the brass itself. nice with a new rifle to know you're shooting ammo that overall is going to give at least average accuracy versus me developing a load at the same time I'm sighting in.
of course now I couldn't afford that, load everything!!!!
Red