howa 243 not grouping

[ssc]

zeroed my howa .243 at 100 yds with federal 75 gr nosler ballistic, and it shot under 1/2" groups. after 7 rounds i stepped out to 200 yards and it shot absolutely horrible. so i cleaned it good and shot 2 more rounds at 200 yds and it shot 3/4". cleaned, shot 2 more; same 3/4" group. i then shot 2 80 grain winchester sp's and they shot 5". i cleaned it again and shot 2 more 80 gr sp's and they hit same hole at 200. so why is when i shoot only 2-4 rounds it starts to open up that much? i was shooting in the vise and let barrel cool 3-4 minutes between shots. gun has 33 rounds through it with brand new nikon on top.

 

[tunacan]

I am not a big fan of shooting with a vise. When shooting off a bench for groups I like to shoot out of a set up that put no unnessecary torque or pressure on my stock.

Shooting at distance is an entire different ball game than punching groups at 100.

Any error in shooting form is highly magnified the further out you go.

Try shooting off of a decent front rest with a bag on the rear. Make sure that the gun can freely move back upon recoil without any interruption.

Try to be consistent in your form also.

If that doesn't help you may want to bed the rifle

 

[shortgrass]

Most factory barrels need a 'break-in' as they're not hand lapped. Breaking -in is basicly burnishing the inside of the barrel to even out burrs or minor tool marks. Those burrs or tool marks can and will collect copper so that may be why you're having to clean it every 2-3 shots. After the marks are worn down the barrel shouldn't collect as much copper. What tunacan said about the shooting vise holds true. A .243 doesn't kick much, use a front rest and rear bag, like he suggested. Might change to bullets designed for bigger game, too, until you feel the barrel is broke-in. Varmint bullets are ment to expand violently, jackets may be soft and leave more copper deposits than a stiffer bullet would. Is the stock 'tupperware'?just my 2 cents

 

[wvcountryboy]

At first I thought you had too slow of a twist but then you said it was a new barrel and it shot better when it was clean.When ever I break in a new barrel i clean between every shot for the first 10 and then every 2 to 20. I dont let it go past 5 shots until after 40. It seems like 40 rounds is the magic number. copper fouling goes down significantly after that point. If you still have bad copper fouling at 40, keep it down to 5 rounds until it gets better.

 

[ssc]

hogue stock, the vise is the type with the pedastal rest on front and back

 

[SC Shooter77]

Are they hand loads of factory ammo? Could be that brand in that weight, if you shoot enough and try different loads and brands you can narrow down what your rifle likes. Just my two cents, good luck! gun)