I recently purchased a model 700 sendero in 300 ultra mag. I cleaned and J&B lapped the bore before firing the first shot. The first shot hit 1 1/2" high at 100 yards. Since it was so close I decided to just shoot it and break it in before adjusting the scope. In the process of firing 25 shots or so, my POI has shifted 3 inches to the left. Is this normal, or do I need to worry about it?
Yes it is normal. Once it's fouled, after a couple three shots it should stabilize though. This is the same reason my barrels are "prefouled" before hunting with them.
3 inches at 25 yards seems a bit excessive, just make sure your mounts are good and run your scope through a repeatability test and this should verify if you are in good shape or not.
My 300 Ultra shots about 3 moa low on the first shot with a clean barrel, sometimes two shots until it works up and stabilizes. It also seems the groups start opening up at just about 25 rounds too, with the combination I tested last anyway.
Let me clarify a little bit. Im shooting at 100yards(actually a laser measured 113) and its not just the foulers that moved.
Its wearing a brand new leupold 8.5 x 25 scope, and leupold dual dovetail mounts.
I agree, the first shot, (fouler) is always 3/4" to the right of the actual group. The gun is shooting pretty good, I went to firing 5 shots between cleanings yesterday. All 5 went into 1 1/4", with the last four neatly tucking in at .700 it has surprised me actually with how tight it is shooting, just this POI change bothers me.
I just reread your first post, I read it too fast the first time and thought you fired them at 25 yards, instead it was 25 "shots".
Sorry about that. [img]images/icons/rolleyes.gif[/img]
At what point is it shifting? Is it between cleanings? I can not stand anything but Ruger or Weaver style mounts, that doesn't mean there is anything wrong with the ones you have, but for me, they don't instill confidence.
Can you detect any marks that would indicate the scope has moved in the rings? I had one move once, and it left no marks at all but just a scratch on the very bottom in the rear. The scratch happened to move under the rear ring and disappear, shaving a little off the tube as it slid forward. The front edge of the ring was not scraping, so it left no mark on the tube as it slid out the front, a half inch later it became visible! I only noticed it when the crosshair started to list a bit, then I kept an eye on it. About the time I knew something was loose, I notices the scratch comming out from under the ring.
Are the bases tight? Did you install this or a shop do it for you?
it has been a gradual thing. the only reason Ive noticed is because I have never made any scope adjustments, and comparing groups, they have moved over the course of breaking it in. it still shoots good groups, they have just moved. I set this rifle up myself, I dont trust regular sporting goods stores to something this important! I used clear fingernail polish on the base screws.
This may be normal, I dont know since this is the first time I have ever NOT made any preliminary adjustments during break in.??
The key is does it move now. When working with a new rifle many things need to "seat" or break in. Check your action screws too, they may loosen just a bit as the stock and action get to know each other.
I rarely worry about the first 20 or so shots since I have nothing to base a judgement on. After the rifle starts to print groups and the POI is set, I watch for any shifts or changes in accuracy.
With everything nice and tight, I doubt you will have any wondering from this point on.
On the change of impact from a clean barrel, I have a couple of rifles that spray after their barrels are really cleaned. In one case, it takes almost 10rds to settle down again. However, once these rifles settle down, they can go for a lot of rounds and still maintain their accuracy. In fact, I clean these rifles only when I am putting them away for a while - rust protection.
I try and clean my rifles as little as possible. After all, what is the point of cleaning a barrel only to need a bunch of fouling shots to settle it down?
I use moly and clean burning powder. Except for one rifle, the rest can go for 100 to 200rds without any fouling issues. I usually clean due to storage, not accuracy problems.
Thanks for the help so far guys! IF IT WOULD EVER QUIT SNOWING I will try it again today. It doesnt show any marks of slippage, and I really dont see how it could move more than a hair litterally [img]images/icons/shocked.gif[/img] because I put an aftermarket level (Avila?) on it slid up against the back of the rear scope ring. This level clamps on the tube just like a set of rings does and I snugged it up pretty tight. So if it has slid, it could only be a MINUTE, pardon the pun, amount. Shooting it will tell me the tale, right now Im just watching it snow. [img]images/icons/frown.gif[/img]