Where have I gone wrong?

[AnthonyR]

I have a Sako 75 in 270 WSM which I am currently using for foxing as my 22-250 is unavailable, I have previously worked up a good load using Hornady 110 gr V-Max and RL17 powder, has been consistently shooting 1/2" at 100 yards and did so only last weekend.

 

I have just made up a new batch using new Winchester brass, which has been FL sized, neck turned, annealed, then neck sized basically the full monty, all done using a brand new Redding competition die set, OAL exactly the same as before ie 20 thou off. The old rounds were prepared using my old RCBS dies, no neck turning etc just basic sizing.

 

Anyway the rifle now groups like a shotgun, 1-2", all over the show.

 

Anybody any idea where I have gone wrong, I was hoping to have improved things, not to have gone backwards

[6mmBR]

It could be that you necked turned the new brass so have altered the neck tension of the new batch of rounds.

The more obvious thing to ask has something shot loose? Action screws/scope mounts/moderator?

Cheers

Dave

[duey]

Was you using Winchester brass before? if not! that is most likely your problem otherwise its back to basic and check all bolts and screws and check all reloading measurements and weights

 

good luck

 

Ian

[AnthonyR]

I checked the action screws before posting this, the front one was ever so slightly loose but only by a fraction, I can't think that that would make such a huge difference. All other screws and the mod were all OK.

 

I think the answer may well be neck tension, but I am at a bit of a loss as what to try except to load up another batch using the old RCBS dies, except I have one more neck bushing that didn't use that is one thou tighter, might have to try that first.

[AnthonyR]

Old brass was all Winchester, once or twice fired only.

[duey]

It was just a thought

may be worth just weighing a few of the cases from the older lot and the new lot and see if there's much difference

also try reloading old brass and see if group comes back

it may just have been that screw!!!

ATB

 

Ian

[andybrock]

If your reloads check out ok I'd have a look at your scope, maybe it could have broke internally and not holding zero, just a thought.

 

Andy

[Andrew]

I have a Sako 75 in 270 WSM which I am currently using for foxing as my 22-250 is unavailable, I have previously worked up a good load using Hornady 110 gr V-Max and RL17 powder, has been consistently shooting 1/2" at 100 yards and did so only last weekend.

 

I have just made up a new batch using new Winchester brass, which has been FL sized, neck turned, annealed, then neck sized basically the full monty, all done using a brand new Redding competition die set, OAL exactly the same as before ie 20 thou off. The old rounds were prepared using my old RCBS dies, no neck turning etc just basic sizing.

 

Anyway the rifle now groups like a shotgun, 1-2", all over the show.

 

Anybody any idea where I have gone wrong, I was hoping to have improved things, not to have gone backwards

 

You annealed new brass? I'm guessing you have a neck tension problem as well.

 

What would make you want to try such a radical departure from (your)proven techniques in an attempt to improve on consistent 1/2 groups from a hunting rifle? In the US we have a saying; "Don't fix what ain't broke!"~Andrew

[eldon]

Got to agree with Andrew, why did you change so many things from what was a proven result. Scientifically you should only introduce one variable at a time and evaluate that change fully before trying something else.

 

Go back to what you had and confirm the rifle and scope is sound. Half inch is good for most people and a standard rig isn't normally going to get much better. Think you are looking for something unattainable and probably unneccessary depending on end use.

 

If you must fiddle then start from your proven load and fudge one thing at once.

[AnthonyR]

Thanks for the replies.

 

Pretty sure the scope is OK as I shot the first lot of the new batch before finishing off the old ones, they still shot fine and I managed to shot 3 foxes with them on Wed night as well, all over 200 yards.

 

I am happy with 1/2" and wasn't really looking to improve it, but I bought a lot of new reloading stuff while in the states recently and was looking to getting to grips with it while I wait for my custom rifle to be ready.

 

Fully take on board the comments about only changing one thing at a time and will go back to the original system for now.

[dully1963]

hi was your new brass (brand new) and not fire formed like your old brass if so try a few old cases through ye new dies and see what happens

just a thought.

hope ye get it sorted nowt worse when you have it right and then it goes all T*TS UP

atb

Andy

[AnthonyR]

Managed to finally find the time, when the wind wasn't blowing like mad, to shot a few the night before last. I had made some more rounds up using the 305 bushing instead of the 306 I had previously used, they shot at 0.6" so obviously a large improvement and proves that the issue was probably the neck tension. I really needed to get this load to work as I had already prepped lots of cases.

 

May now try a 304 bush and see what happens from there.