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Two Points of Impact

Posted: Sat Dec 18, 2010 3:23 pm
by Neil S.
Hello all, I am looking for some help. I have been reloading for my savage 12fv, shooting mostly 39 BK's with RL-10X, and was finally starting to find a nice load when my gun started shooting to two points of impact:

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I figured that it was the cheap scope that was causing the problem, so I saved up and bought a Leupold VX-3 6.5-20x 40mm scope and installed it properly (lapping, alignment bars, proper torque.... etc). I also bought an adjustable metal front rest and a protector rear bag which I filled properly so that I would have a stable rest. Shot it today with the load that had been promising..... and the groups were similar :eew: .

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I flinched on one shot which accounts for the hole in between the two distinct groups. When I first noticed it, 32 V-Max reloads seemed to work as they had, ~ .5 inch groups. I assumed that the lighter recoil wasn't enough to jar whatever was shifting... I'll load up some 32's tomorrow for testing. The stock is factory and very flexible. Could this be the issue? Maybe it needs to be bedded? Suggestions appreciated.

-Neil

Re: Two Points of Impact

Posted: Sat Dec 18, 2010 3:58 pm
by larr
could it be that the barrel is heating up? is it a sporter barrel on your rifle?

Re: Two Points of Impact

Posted: Sat Dec 18, 2010 4:15 pm
by Neil S.
Larr, it is a heavy barrel. Barrel heat doesn't seem to be a problem, as the change in impact is inconsistent, jumping from one group to the next during a string of fire. I have tried allowing the barrel to cool between shots with no luck. Also it was 32 degrees today and the barrel barely got warm. Thanks for the quick reply!

-Neil

Re: Two Points of Impact

Posted: Sat Dec 18, 2010 5:44 pm
by larr
bedding the action and floating the barrel is probably the answer.if you have extra cash i would buy a
H-S Precision stock,i own 2 of them both on savages. i think they are the best feeling and sturdiest stock out there but thats just my opinion. let us know how the 32's shoot.

Re: Two Points of Impact

Posted: Sun Dec 19, 2010 9:24 am
by 204cat
how is your trigger pull ? is it consistent ? talking about your trigger and your finger pull. <insert joke> . now and then i get the trigger catching and get a flier. never more than half inch out or off target though.

Re: Two Points of Impact

Posted: Sun Dec 19, 2010 10:49 am
by Neil S.
204cat, the trigger is the accutrigger and the best I have ever used. I have done quite a bit of dry fire practice and it seems very consistent. It was driving me crazy for a while trying to figure out if the loss of accuracy was due to me or the equipment and I do believe now that my trigger pull is not the problem.

Also, I did some dry fire yesterday while aiming at the target. It seemed to me that sometimes the crosshairs would shift about half an inch vertically on target as I heard the 'click', but other times they were rock steady. This leads me to believe that SOMETHING is shifting. Or it could be my imagination :? .

-Neil

Re: Two Points of Impact

Posted: Sun Dec 19, 2010 11:36 am
by RUD
Probably an equipment problem of some sort. But have you had another person try and shoot it to see how they do? Just a thought. Rudy

Re: Two Points of Impact

Posted: Sun Dec 19, 2010 5:27 pm
by Wrangler John
One thing to check is that either one of the action screws (especially the front) is not interfering with the bolt. After awhile, the screws may seat down in the bottom metal or pillar(s), and touch the bolt. When this happens to the front screw, it can tilt the floating bolt head and toss a shot, depending on how the case chambers. I had this happen to a Savage Target Action. The screw just barely touched, I couldn't feel it and the bolt closed normally. There was just a slight mark on the locking lug.

Another cause can be an internal box magazine not properly seated in the action, where there is interference between the action and stock (the action is tightening against the magazine box rather than the stock). If yours is a top loader that has the Magazine Retaining Clip, #7 in the parts drawing, that retains the magazine box, be sure it is properly seated in the slot on the box and not distorted.

Finally, check that the action screw torque is set to factory recommendations. Also check that there isn't too much pressure between the rear tang and the stock, many Savages prefer minimal pressure reward of the action screw nearest the trigger.

Regarding your comment about seeing the POA shifting when dry firing. Usually this is normal - we have all seen our aim knocked off by muzzle blast from nearby shooters at the range. There are two things that may relate. If the cocking pin on the firing pin assembly hits the bolt body before the firing pin hits its stop, it can play havoc with firing pin protrusion and kink the bolt sideways. This may toss a shot up to the left as the cocking pin on the Savage travels on the right side of the action, not the bottom as in the Remington and Mausers, etc. There should be clearance between the cocking pin and the bolt body (in the cam area) when the pin is in the fired position. See http://www.switchbarrel.com/Spring.htm read down to the second to the last paragraph. Also, firing pin protrusion should be somewhere between .040" to .060". The second is be sure the scope rings aren't tightened around the scope too much, as this will stress the erector tube and cause it to jam or bind. All that is needed is 15-18 inch pounds on the screws. Another factor is that the rings need to be inline with each other, or stress can be introduced. In some cases that requires either Burris Signature rings with the bushings, or a Farrell type one piece mount glass bedded to the action contour.

If there is too much oil and gunk in the bolt it can cause problems with function leading to ignition problems in cold weather. Dismantle the bolt, clean with solvent and lightly lubricate.

Re: Two Points of Impact

Posted: Mon Dec 20, 2010 5:03 pm
by Valar
If It is a factory barrel they tend to copper foul after consecutive shots. Also is the barrel free floated? I have a factory rem 700 vs in 308 that gets a bit erratic after consecutive shots with jacketed bullets. Did you break barrel in properley? If Barrel isnt floated it could as things warm and swell be creating pressure point on barrel and change poi?

Re: Two Points of Impact

Posted: Tue Dec 21, 2010 8:58 am
by Neil S.
Just a quick update, I was checking the action screws, as per Wrangler Johns suggestion, and making sure everything was tight when I reaized that I had only snugged the windage screws on the bases :wall: . I am assuming that this was the problem and will report back when I have time to test fire. Thanks for all the help!

-Neil

Re: Two Points of Impact

Posted: Tue Dec 21, 2010 6:22 pm
by struttin
i'm having the same problem with my 204 sounds like we might have the same guns. mine shoots great groups then the point of impact goes to the same elavation as yours but to the right. this has driven me completly crazy. i sent the scope back to the manufacture and it came back with no problems. the trigger seems above average. might get a new stock or just move on to anothor 204. This gun is used for prairie dogging so the barrel does get extremely hot but i have other guns that i shoot and dont have this problem under the same conditions i've put this on the back burner till the 1st of the year then if i can't find a solution it's gone.

Re: Two Points of Impact

Posted: Mon Dec 27, 2010 9:26 pm
by Neil S.
Well I finally got a chance to shoot today. Its been terribly windy for the last couple days, but this evening the wind died completely so I grabbed my gear and headed to the bench. I was only able to shoot one group, as the sun went down and the light slowly faded away:

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The low hole was the first bullet out of a cold bore. I guess all that was needed was to tighten down the windage screws on my Leupold bases! Life is good. Happy holidays everyone!

Re: Two Points of Impact

Posted: Thu Dec 30, 2010 10:47 pm
by M_D
Loose screws strike again. Glad you found the problem.

Re: Two Points of Impact

Posted: Wed Jan 19, 2011 10:36 am
by bow shot
Be sure to weigh your brass.... My hornady brass caused me similar problems. What a mess that was!!

Inconsistent weight may be indicative of inconsistent case capacity.. which mirrors the effect of inconsistent powder charges. Not much room for error with that tiny little .204 case!!

Do yourself a huge favor: Weigh 'em, don't ignore it!!