The Accurate Reloading Forums
.300 win mag after 15 shots opened up like a softball

This topic can be found at:
https://forums.accuratereloading.com/eve/forums/a/tpc/f/2511043/m/5081024721

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
wasbeeman
Could 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. Wink


Aim for the exit hole
22 February 2010, 18:31
icemanls2
I 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
jeffeosso
scope mount is loose.. likely bases


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about
the416AR, 458AR, 470AR, 500AR
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
http://www.weaponsmith.com
22 February 2010, 19:18
icemanls2
Nope, checked em. Rings and bases are tight.
22 February 2010, 19:20
BECoole
Bum scope?

Check with a collimator.

Maybe loose bedding screw?
22 February 2010, 19:25
icemanls2
I 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
plainsman456
I would clean it and try again.
23 February 2010, 00:53
BECoole
Yeah, 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
IanD
Did you let the barrel cool completely between strings?
23 February 2010, 15:16
Ingvar J. Kristjansson
Don’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
icemanls2
Still 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 Red
off 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