Accuracy issues

[lucky hunter]

I have a savage 93 with stainless bull barrel, accutrigger and thumbhole stock. I am shooting 17 grain vmax ammo off lead sled. One day I can put 5 shots in 1 hole at 100 yards. Then days like today I'm getting 1"+ groups with same exact set up. Why would this happen? I don't think it's me as I shot my other rifles excellent today.

[flphotog]

Have you by any chance adjusted the action screws at all?

[lucky hunter]

I have not

[RickD]

Just a suggestion. The next time it does that, try sandbags. My 93 does not like the lead sled. I can't explain why.

Rick

[lucky hunter]

Gotcha. Its just weird because I always shot it off a lead sled (both times when it shoots very well and when it does not)

[SavRimfire]

Unless the ammo was out of the same box and/or Lot# it very easily could be the ammo. Unfortunately, rimfire ammo can vary quite a bit from lot to lot. I've shot my best AND worst groups with Hornady 17gr Vmax HMR ammo. It's common to have 100 fps, or more, variance in 17 HMR ammo within the same box of 50.

Sometimes you luck out and get a Lot# that for who knows why is consistent and shoots outstanding then go pick up a different box of the exact same ammo from your local Walmart and it shoots two inch groups.

[Hotolds442]

I've been sorting rounds by weight for a couple of years, and found that's the most consistent way of ensuring accuracy in the HMR.

[lucky hunter]

I've been sorting rounds by weight for a couple of years, and found that's the most consistent way of ensuring accuracy in the HMR.
I might have to try that. What is your process in doing so? What weight range do you "batch" together?

[SavRimfire]

Weight sorting certainly won't hurt anything but don't be to surprised if it doesn't change much either.

I've pulled apart quite a few different rimfires before and the powder charge and bullet weight has always been very consistent. The biggest difference in weight has always come from the amount of priming compound and actual case weights. I've done a good amount of chronograph testing with weight sorted ammo and was actually a little surprised when there seem to be no real pattern to velocity spreads. I had just as many of the lighter weight ones shoot faster than I did of the ones that weighed the heaviest. I wish there was a way to measure the amount of crimp they put on the bullets and how consistent it is from round to round because if it's not, I could certainly see that causing significant changes in pressure which would result in varying velocities. Also, rimfires headspace off the rim so measuring rim thickness with a rimfire headspace gauge for the 17 HMR could be of some value as well. Or, you could do like my friends always tell me, when I bring up the topic of inconsistent rimfire ammo, and just shut up and shoot the darn thing. LOL I know they're right but the OCD and "Tinkeritus" in me just won't allow that to happen.

[Poor Shot]

Any possibly of a loose scope?

[lucky hunter]

I checked everything and it seems tight