What do I do now???

[Guest]

Heres the deal...Getting 1.5 MOA from a sub 1/2 MOA rifle...
I know the rifle is OK, as it shoots the original load under 1/2 MOA(75 gr VMAX), and I'm wondering what I should change with the new load first...
Cal. .257 DGR 1:12" tw
Load.. 100 gr Nosler BT
46.0 gr H4350
Federal 210M primer
I tried several different charge weights and seating depths, and best seemed to be the 46.0gr weight and .015" off the lands. This load is giving me three or four in sub-.75" groups, but the fourth or fifth shot always opens the group up to around 1.5"....I'm not sure whether to change the powder or the bullet first...
The barrel is a #5.5 taper(fairly heavy) and isn't getting too hot. I wait until the barrel cools until it is warm to the touch before I continue firing. It is fully floated and is bedded in a McMillan stock, the screws are all torqued with a torque wrench and the scope is a NF NXS.
The groups don't really have a particular shape, although they aren't stringing vertically.
I'm thinking that a switch to R19 or N560 might be the ticket. I also have some Winchester primers, but I have yet to have a problem with Federals...

 

[Nodak7mm]

CJ,

I use the same components in my 257AI, a little more powder with great success. 1/2" groups are the norm provided I do my part. I used to use RL19, but it tended to sway with the temp, but it was/is a fantastic powder for this combo. If I were you, I'd change bullet first.. I couldn't get my barrel to shoot v-maxes, decently.

Nodak

[ 10-28-2003: Message edited by: Nodak7mm ]

 

[Guest]

Every round I've fired thru this gun has gone thru the chronograph and throughout all the load testing, the largest ES I have had has been 31 fps, and that load produced the smallest group..go figure...The average ES is running in the teens.
I know, I know, ..Crack open the box of 100gr SMK's...

[ 10-28-2003: Message edited by: Chris Jamison ]

 

[*WyoWhisper*]

Chris,

Go back to varget!!!

Also if you are gonna shoot the 100 gr. bullets.. you might want to think Flat base...

Also if you're gonna shoot 100 gr bullets...

Push them as fast as you can with that twist!!!

 

[speedbump]

With a 1:12 twist...I'd try more in the 75 grain range first. You oughta have the answer quick!

 

[MAX]

I think twist is your problem, but that's only the purest form of Sunday AM speculation, unsupported by fact or even deep thought. Try the 85 BT's...