Group Therapy Help

[EOD Diver]

Guys,
Would appreciate any input for my daughter's M70 SG in .270 Win. I've been trying to get it to go sub-MOA for a while now with no luck. She'll put two almost touching or under .5" and then the third at around 1.25" (in no particular order). Is this indicative of anything (bedding, receiver torque, etc.)? The rifle is stock, except for a lightened trigger. When I got the rifle, I had my gunsmith mic the bore and it came out to .279. Unfortunately, this is the 3rd M70 (post-64) that I've had with that problem. I sent it back to Winchester without ever having fired a round through it, explaining that it had a big bore. They test fired it in their tunnel and said it passed their QC by putting factory Federal 130 Game Kings under .5" and sent it back to me. I've tried different charges and COLs on 140 ABs and PTs, but can't seem to consistently get it under an inch. I'm thinking my next step is to try different primers and see if I can't get some 130 ABs. Again, any input is welcome and appreciated. If it were purely a deer rifle, I'd be more than happy to try to duplicate the Federal load, but it's for elk too and you guys know how I love my ABs.
Joe
140 AB/PT
IMR 7828ssc
RP Brass
RP 9.5 Primers

 

[velvetant]

If that's the bullets you really want to use start with a primer change.
Might not like the bullet/powder combo so try a different powder. I used H4831 in my 270win and 270wsm
If you still don't get the groups you like go up to 150 NAB or NPT or drop down to the 130s
Pick up a box of Federal ammo and see if you get the same result, If you do you know it will shoot.

 

[joelkdouglas]

You could try to shoot bigger groups than 3 shots. If you're getting double groups, you might try deeper bullet seating.

Maybe a switch to magnum primers? For no reason other than they're different.

 

[AzDak42]

How long are you waiting between shots?

I saw an M70 in 30-06 string shots up to 2" vertically when they didn't give it at least a full 60 count between shots.

Any pics of the groups?

 

[sask boy]

I have been shooting 130gr. ABs out of my 270win in a CDL for a number of years. I use IMR4350 and I get sub 1"moa continually likely closer to .75. I am shooting 54grs of powder but as always every rifle is different so you should start lower and work up. :mrgreen:
I have recently seen here on the forum some pretty impressive groups using RL22. but have not tried it yet.

Blessings,
Dan

 

[SJB358]

Joe, if you are getting groups like that, I might try a primer swap and see what it does? Can't hurt and it's cheap too..

If that doesn't work, maybe try some RL22.. Seems like some great groups coming in from that powder lately as well.

Good luck buddy, I hope you get it worked out. My 264WM is doing much the same thing. I think once I narrow down the powder charge, I will try a primer swap and see what it does as well..

 

[DrMike]

Joe,

I can't help but think that you have a pressure point somewhere. The fact that the deviation is in no particular order would indicate that you're actually seeing a normative group, however. That being the case, I'd take a hard look at OAL. I've had rifles that required strange jumps to the lands. I had one rifle that wouldn't give me a decent group no matter what bullet I tried and no matter what powder/charge I tried, until I went to a bullet with an exaggerated bearing surface and allowed a 0.250 inch jump to the lands. Then, it was a consistent 0.25 inch shooter.

 

[CAhunter]

57-59gr of H4831SC is what you should try with those 140AB. As stated above you may have to play with the OAL also. I would also say free float the barrel and bed the action.

 

[bbearhntr]

Joe, if you are getting groups like that, I might try a primer swap and see what it does? Can't hurt and it's cheap too..

If that doesn't work, maybe try some RL22.. Seems like some great groups coming in from that powder lately as well.

Good luck buddy, I hope you get it worked out. My 264WM is doing much the same thing. I think once I narrow down the powder charge, I will try a primer swap and see what it does as well..

+1 on the primer change
This article touches on it being the cause of the two together and one out problem...
http://www.24hourcampfire.com/long_range.html
I haven't been loading long enough to find out for myself, but it is a cheap variable to rule out. Good luck and let us know what you find

 

[EOD Diver]

ALCON,
Thanks for all the input. The rifle came from the factory with glass bedding and the barrel was pretty generously free floated. I can run a pretty generous piece of paper (note card) up the channel to the tang without any interference. It's got leupold dual dove tail rings that were line bored to eliminate stress. I tried messing with with OALs today. My usual is 3.368 with the 140 AB. I knocked it down in 0.030 increments for 3.338 and 3.308. The groups actually opened up when I decreased the OAL with my most (typically) accurate charge of 57.6 grains of IMR 7828sc. Tonight I'll try some different primers and resetting my seating die back to 3.368 OAL. A buddy left some RL22 here so I might give that a try too. Local sporting goods hasn't had 130 ABs for about 4 months, so guess I'll put in the call to Midway or Cabela's tonight. I guess I can't cry too much, as I've yet to even change primers or powders. Thanks for all the suggestions guys.
Joe

 

[JD338]

Joe,

I would give H4831 and RL 22 a try.

JD338

 

[CatskillCrawler]

As mentioned, I think you'll find your solution with one of these powders: H-4831SC, IMR-4350, IMR-4064 and RL-22.

I needed to make the 140gr Accubonds jump much longer than with most bullets to make them tighten up in my .270Win.

 

[hubcap]

ALCON,
Thanks for all the input. The rifle came from the factory with glass bedding and the barrel was pretty generously free floated. I can run a pretty generous piece of paper (note card) up the channel to the tang without any interference. It's got leupold dual dove tail rings that were line bored to eliminate stress. I tried messing with with OALs today. My usual is 3.368 with the 140 AB. I knocked it down in 0.030 increments for 3.338 and 3.308. The groups actually opened up when I decreased the OAL with my most (typically) accurate charge of 57.6 grains of IMR 7828sc. Tonight I'll try some different primers and resetting my seating die back to 3.368 OAL. A buddy left some RL22 here so I might give that a try too. Local sporting goods hasn't had 130 ABs for about 4 months, so guess I'll put in the call to Midway or Cabela's tonight. I guess I can't cry too much, as I've yet to even change primers or powders. Thanks for all the suggestions guys.
Joe

What velocity are you getting with 57.6 gr. of 7828? I only got 2600 with 57.2. The nosler book-5 says 2977 with 57.5. Hmmmmm

 

[PJGunner]

I have four riles chambered to the .270 and every one has given me my best accuracy when using 150 gr. bullets. :shock: As the rifle in question is a Winchester, I'll just mention my M70 XTR that I found at a gun show. At first I thought it was a Featherweight that someone had replaced the stock with a McMillan but it turned out the stock was factory and Featherweights do not have 24" barrels. I bought a box of Winchester 150 gr. powerpoints to test the gun and groups were mostly in the .75" range, the worst one doing one inch. My handloads using the 150 gr. Sierra game King eun right at the .75" range as long as I'm doing my part. Unless you can find some Winchester Magnum Rifle Powder (WMR) passing on the load would be a waste of time. I'll just say it's been a good powder in my .270 and .300 Win. Mag.
Before I went to WMR, I used 57.0 gr. of H4831, Winchester brass, CCI 250 Primer and the 150 gr. Nosler Partition. That load shot sub-MOA in two different rifles chambered to the .270.
I've never tried any of the 140 gr. bullets in my rifles as accuracy with the 150's has been very good. When I got my first .270, I tried 130 gr. bullets but accuracy while decent was not what I wanted. One day when buying more bullets to try, I accidently got a box of 150 gr. bullets and the rest was history, at least for my rifle. (I only had the one way back in 1973. :lol: )
If elk is on the menu, I think I'd take a look at some of the 150 gr. bullets and give them a try.
Paul B.

 

[EOD Diver]

Thanks guys, problem solved!
With everyone pushing me toward 4831 or RL 22, I got some RL 22 from a pal last night and loaded a ladder. Things really looked good after 57.5 went into .81". Got better when 58 went into .68". 58.5 went into 1.3, but 59 grains slipped back into .81"! Damn, I wish I wouldn't have chased my tail for so long with the 7828 loads. I really appreciate everyone's input and will mess with primer combos after deciding on a load to try and tighten it up further. Chalk me up as a new fan of RL 22.
Thanks Again!
Joe

 

[DrMike]

Great to hear that you've found the powder that works in your rifle. Congratulations.

 

[bbearhntr]

Glad to hear RL22 worked so well for you! I was tring to get IMR7828 to work in my .257 WBY without any luck and RL22 made all the difference in the world. Happy shooting!

 

[SJB358]

Thanks guys, problem solved!
With everyone pushing me toward 4831 or RL 22, I got some RL 22 from a pal last night and loaded a ladder. Things really looked good after 57.5 went into .81". Got better when 58 went into .68". 58.5 went into 1.3, but 59 grains slipped back into .81"! Damn, I wish I wouldn't have chased my tail for so long with the 7828 loads. I really appreciate everyone's input and will mess with primer combos after deciding on a load to try and tighten it up further. Chalk me up as a new fan of RL 22.
Thanks Again!
Joe

It is a HUGE favorite of mine Joe. It is one of the best in my M70 270WSM. Can't hardly beat it.

Funny, as in my rifle, IMR7828 is just about as good.. Guess that makes two M70's!