243 grouping

[SkipB]

Guys I have a 243 that wont group in a bucket. I built up a heavy barrel 243 using a 9 twist McGowan barrel in a floated Boyds stock with a 6x24 Vortex scope. I have used 43 grains of Superformance with a 100 grain Interlock with a .020 jump and it wont group in an 8 inch circle. I have used 42 grains of IMR 4350 under a 90 grain Speer flat base .020 jump and it groups about 4 inches. I used 34 grains of H-4895 under a 90 grain Speer flat base with .020 jump and again maybe a 3 or 4 inch group. All of this is at 100 yds and cool temps. My next powder is H 4350. It seems like the lighter bullets group a little better but not by much. This gun has 24 rounds through it and I followed a good break in procedure. Anyone have a suggestion?

 

[Airedale56]

Seat your bullets deeper.
Try .030" to .040" jump.

Just did the same thing with a 6.5 SAUM and 140 Nosler Partitions. Longer jump shrank the group size to under an inch.

Try that.

 

[Rob01]

First off 24 rounds is barely used. Break in with the old shoot one and clean is a waste of time but if you did it you did it. I would give it a very good cleaning now. Down to metal with a good solvent. Then clean it that way after your next 3-4 range trips so the throat is smoothing out some. It usually takes about 100-150 rounds through a barrel before it ready for a set load. The barrel can speed up some also around that mark.

Second you need to shoot more rounds through the barrel before any good load work up. You can start figuring it out now but going from one powder and bullet to another to another isn't really the best way. Test one powder and bullet and find a load. That said 8" is crazy. I would try a different scope and some factory ammo to check the rifle out.

Also 9 twist is a little on the slow side to start getting in that 100 grn+ area. My match .243s have had 7.5 twists and shot up to 115grn bullets great.

 

[can1010]

if you are getting 4-8" groups you need to look elsewhere besides your reloads. first is your boyds stock bedded with pillars? if not start there they are known to put uneven pressure on the action if used unbedded. second would be ring and base screws and check if your scope is slipping in your rings, they might need lapping. also if your barrel is a prefit make sure it is tightened to the proper torque.

 

[vancewalker007]

Once you have verified that all the mechanical issues (ie. stock fit, stock screws torque correct, scope mounting correct, scope operating properly, barrel crown OK) with the rifle are OK then I'd do an OCW style powder ladder recording the group sizes and the velocities before I wasted any more components guessing on what powder load to try. Find a powder load that is in a stable node and go from there. Your guesses about powder loads could be on the edges of pressure nodes causing your velocities to be all over the map shot to shot. Once you have a known stable powder load try seating depth tests using the powder load and seating depths in 0.005in steps. This should quickly narrow down where your accuracy nodes are or are not. There is a chance the rifle hates the bullet you are shooting. It happens.

 

[Coyote Shadow Tracker]

Guys I have a 243 that wont group in a bucket. I built up a heavy barrel 243 using a 9 twist McGowan barrel in a floated Boyds stock with a 6x24 Vortex scope. I have used 43 grains of Superformance with a 100 grain Interlock with a .020 jump and it wont group in an 8 inch circle. I have used 42 grains of IMR 4350 under a 90 grain Speer flat base .020 jump and it groups about 4 inches. I used 34 grains of H-4895 under a 90 grain Speer flat base with .020 jump and again maybe a 3 or 4 inch group. All of this is at 100 yds and cool temps. My next powder is H 4350. It seems like the lighter bullets group a little better but not by much. This gun has 24 rounds through it and I followed a good break in procedure. Anyone have a suggestion?

Go back to the person that chambered and crowned the barrel and have him/her look it over.

 

[Justice1327]

4-8" groups are not a reloading only problem. If truly measured…these groups are a hardware/barrel problem.

 

[Rob01]

Yeah definitely give the whole rifle a once over. Also make sure the barrel is free floating and not touching even when you are behind it. We had that happen to a student once at a class and it was free floated when he wasn't on the rifle but he got behind it and laid his head on stock and there was touching of the barrel to stock.

 

[SkipB]

I floated it and the stock was pillar bedded by Boyds. McGowan fitted the barrel to the action for me. I have tried both a Vortex 6x24 and a Nikon 4x12, The bases were set up in a milling machine so they are true to the barrel and everything there is solid.

 

[Jud96]

Like others have already mentioned, step away from the reloading bench and look at your rifle. Check your action screws, make sure the barrel is actually free floated, check your scope base screws, check your ring to base screws, scope ring screws, make sure your barrel isn't touching the stock when you're resting the forearm or loading the bipod. Pillar bedding from Boyd's doesn't mean much other than you have pillars that may or may not be touching the action and you still don't have any actual bedding in the recoil lug area or the rest of the action. If everything mechanically checks out, then I'd go back to the gunsmith and have him look at it and check the barrel out.

 

[can1010]

when Boyds installs pillars they press fit them no glue atleast on the ones i have seen you still need to do a proper stress free action bedding job and glue pillars. McGowen makes a decent barrel better than 4-8" but maybe a bad one got out the door.

 

[SkipB]

I have another stock I`m gonna try on it this weekend just to see if it changes anything. It was floated for a much bigger diameter barrel so I know nothing will be touching

 

[Rob01]

What action are you using?

 

[SkipB]

What action are you using?

Mauser 98