Need help with my 450m

[valvesinmyhead]

I have a Encore Pro Hunter with an MGM 450m 26" barrel with 1-14" twist.I was shooting factory Hornady 350gr FP. Scope is a Nikon Omega with muzzle loader BDC and 5" eye relief.
Went out to shoot to get some practice Sat. It was already sighted in. This is a new barrel with 10 rounds down the tube to sight in. Cleaned barrel before practice. Used a chair and shooting sticks. First round 4" high. Next three around the bull in a 3" group. Shot at some 1" dots on the target and was about 2- 1 1/2" away every time. Barrel after 7 rounds was barely warm. Took the barrel off and practiced with my 6.8 SPC barrel. An hour later back on with the 450 for some more shooting. First few rounds are fine. 2" away from POA. Everything good I thought just me. Then everything went bad. Could not hit anything I aimed at. Not even close. So I got mad at my self for shooting so bad and decided to shoot a group to see what I'm doing. I thought it was me anticipating recoil. Shot a three round group that measured 2" and it was 12" low and to the left 4". OK I know now it is not me darnet.
So did my scope go bad?
My barrel fouled ?

[Grizz66]

First things first check your base screws and ring screws, then clean up the barrel and go back to the range might have to readjust scope if rings were lose. If the gun is still misbehaving swap out the scope to a proven scope from another gun. I have been threw this a few times it is aggravating, but it's the nature of the beast sometimes.

[jro45]

Iv'e been threw the whole mess before . Come to fine out that my rifle bolt was loose. So I had the rifle beded. That solved my problem. Now she shoots 1 to 11/2" groups at 200 yds.

[valvesinmyhead]

Finally had time to go shooting. Took out the 450m. Before I went I cleaned the barrel with Hoppes #9 then a copper solvent. First shot an inch low and right. Adjust scope a few clicks. Second shot 4 inches low! Third 6 inches low. what in the world!
So I walked a hundred yards of shame to take a closer look. Went back. First shot on the money. Second 8 inches low 3 inches right. Third 4 inches low 4 inches right. What the heck is going on. A few more groups with the first shot being good and then the rest off. Big. The last was all three shots in a inch and a half group. So 24 rounds to get a good group? Is the 1-14" twist to fast for the Factory Hornady 350gr FP?

[Grizz66]

I'll take another stab at this did you try different ammo yet? Check to see if the forearm is touching the frame I hear this is a common problem and can play hell with accuracy. As far as twist rate I think 1in 14 is fine for the 450 marlin shooting 350's I beleive that was the original loading. It just don't make sense to go from 1 1/2 groups to 12" groups. Did you prove the scope is holding a zero? If all else fails send the barrel back to MGM with targets or pics of targets as proof of a problem and have them evalulate it ie; chamber straight,right twist rate ect. Hope this helps out a bit.

[valvesinmyhead]

No I have not tried any other ammo yet. Maybe that's where I should start. I think the scope is good because I can hit the bull with the first shot. After I wait a few minutes. The forearm does not effect the accuracy with my 6.8 SPC or .22lr barrels.

[valvesinmyhead]

Well it was the ammo. Shot some Hornady 325gr FTX and it was 1" to 1 1/2" groups no problem.
Thanks for the help.  Todd

[valvesinmyhead]

The group all over the place is the 350gr FP. The very next group I shot was the 325gr FTX. Top right.
Shot at 100yds.

[the great orator]

the marlin barrels are 1 in 20",  I wonder if your twist is a little too fast for heavy bullets

[valvesinmyhead]

Well MGM said 1-14" will stabilize heavier bullets. I will have to try Buffalo Bore 430s.