Why first shot of each magazine low and or left 1" at 50 yards?

I've only had a Mark II BTV for a couple of weeks, but I have about 600 rounds experience now, including on benchrest rimfire match.

On two very windy days 20-30 mph, with the wind at 12 to 2 o'clock, the first shot from each magazine hits nearly 1" low or low left at 50 yards, even after leaving the bolt closed while loading the magazine. I can't figure out what I'm doing differently on the first shot of each magazine. Time from last shot of previous magazine to first is maybe 20 seconds. I use a bipod and rear bag. BTV barrel is free floating in thumb hole stock. Groups are excellent except for first shot of five. Action screws are tight. Stock is not bedded. Stock Accutrigger. Norma Tac 22 lead nose 40 gr and Federal GMM ammo do the same thing.

I'm open to any ideas. Will try on calm day as soon as we have one just to see if it is some quirk of barrel cooling or something like that. Most likely shooter doing something wrong in my opinion.

I will also check to see that there is a lot of clearance at free float, not just a dollar bill's worth, cold and no load on the bipod.

Joe

One of the few magazines where the first shot hit center, so all five were good.

http://joelynch.smugmug.com/Firearms...IMG_1731-M.jpg

Joe

Good shooting. When's the last time the barrel has been cleaned?

About 50 rounds ago. Didn't change anything.

Joe

Not sure then. I have the savage mkii FV and mine does not do that. Have you tried loading one round at a time?

I'm going to put in the Apachee Trigger and modify my hold slightly after making sure there is a bunch of clearance on the stock at the barrel. It should be a simple fix. I will also have a stack of magazines to use so I can at least see if the first shot change is due to the time loading the magazine or just something happening when I loosen grip, swap magazine, run the bolt, and shoot again in 5 seconds instead of 20.

Joe

What if you shot first round... Open bolt...wait 20-30 seconds... Shoot second round... Then see if they fall together? (In other words, turn your "second" shot in to another "first" shot, to try and eliminate the time delay between magazines as a factor)


Just thinking out loud.


(?)

Good idea, FIP. I got two 10 round magazines in today so now I have 3 five rounders and 2 ten rounders. Will do some experimenting on Sunday.

Joe

I shimmed the front action pedestal and clearanced the right side of the front end of the stock today. The action was rocking in the stock. I will bed it after I do the trigger job, but will try it on Sunday to see if what I did today has any effect on the first shot low left hits. I think it might help. Bedding might fix it permanently. Might.

Joe

Good results this morning with the shims. Definitely changed the first shot hit to much closer to the next 4 and now a little high instead of low. I am going to bed in at least the action pillars to the wooden stock. Also ordered the DIP plate and trigger guard with the longer screws. All I was looking for with the shims was a change and I got it.

Joe

Bedding the action to the stock helped/eliminated the problem. See the short video below from this morning. Apachee trigger is good, too.

http://youtu.be/r3gD-aG8t_U

Joe

Cool.