Vertical shot stringing question

[johnpb]

Does anyone know what might be causeing my shots to start rising vertically? The other day I was putting 3 shots in about 1 1/4" at 85yrds. using 2 50gr 777 pellets and T/C 300gr XTP's. I'm wanting to find something less expensive so I went out today and tried some 777 ffg with the same XTP's. 100gr 777 and the 300XTP's shot 2 1/4" high 1st shot, 3 1/2" high 2nd and 4 1/4 the third. I tried 2 777 50gr pellets and 300 XTP and 1st shot was 2" low, 2nd shot 1" low and 3rd was on the X. Like I said the other day it was shooting 1 1/4" circle at 85yrds. All shots are almost straight vertical. I'm shooting a CVA Kodiac Magnum with a 28" barrel and a Barska 4-14X42 scope.

 

[frontier gander]

If it was consistent with the pellets and then went haywire with the loose powder, it comes down to, You having the find the golden load thats performing well. Got to work up loads to find its sweet spot.

Sounds like it was doing fine with the pellets.

Maybe try some pyrodex. T7 used to throw my shots all over the place.

 

[Semisane]

The first thing I would suspect is inconsistent seating pressure on the bullet. The second thing I would try is upping the loose powder charge by 5 grains, then 10 grains.

 

[Lee 9]

THERE is one obvious problem in what you said. Two 777 pellets are equal to 100gr of RS Pyrodex not 100gr of 777, why they did this ignorant confusing thing is beyond most of us but that is the way it is.
If you are not swabing between shots you POI is liable to climb. Try 80 or 85 gr of loose 777 to equal yor pellets. Lee

 

[cayuga]

Another thing I found that can cause stringing is you are forcing the rifle in your address. Many times I catch myself changing my grip or my hold or pulling tighter or what ever. All of that can have an effect on how the shots will print. Make sure you hold the same each and every time, and swab between shots. See if that does not help.

 

[toytruck]

Check the scope bases and rings to make sure they are still tight. Normally vertical stringing is due to the barrel getting hot and not cooling enough between shots, read that somewhere.

 

[Anonymous]

There is nothing I can say that hasn't aready been said GREAT JOB GUYS

 

[n8dawg6]

how hot was it when you were shooting? an overly-hot barrel causes shots to string vertically. in my shooting experience, this has proven to be a fairly inflexible rule.

 

[johnpb]

Thanks guys, after reading everyone's thoughts I think cayuga may have hit it on the head. I have been swabbing between shots but I did move my hold to try to really get a steadier hold on the gun. It was about 75-80 degrees yesterday morning but it was about 85-90 the other day when it shot better. Both times I had shot about 6 times before I got the best patteren. I will try going back to just letting the barrel set on sandbags and putting my left hand under the rear of the stock as before. Its amazing that just a little difference in your hold would change POI by a couple of inches.

 

[Reese]

I will try going back to just letting the barrel set on sandbags and putting my left hand under the rear of the stock as before. Its amazing that just a little difference in your hold would change POI by a couple of inches.

You mean the forearm on sandbags, not the barrel right? I get the best groups from the bench by not holding the forearm and use my left hand to steady the butt stock (right handed shooter). Bullet seatting pressure is very important to.

 

[Lee 9]

Also be aware of the fact that putting the forarm on the sand bags is more likly to shot to the same POI as shooting off hand, on some guns putting the barrel it self against the sand bags will change the load that groups best because it changes the whip or vibration of the barrel. Lee

 

[johnpb]

I'm trying to be as consistant as I can by feel with seating pressure and I did put my left hand over the barrel where the forarm sat on the sand bags for a few shots to try and make a steadier rest. I do want to replicate a hunting situation as best as I can. Most times I'll be in a treestand and use the arm rest to steady my shot. I never thought about putting my left hand over the barrel like that would change the poi. Most other times when I've been in a treestand thats where I put my left hand to steady the shot but it didn't hurt on the outcome. I give it another try and see if it stops stringing the shots vertically.

 

[Lee 9]

Any thing that puts any pressure on the barrel will change the POI in fact I have seen different pressures on the forearm and stock shange it, there is one rubber cushion rest on the market that one of our club bought, we all tried to out smart it, it did not make any differance who shot it or what gun was put on it it would change a minute of angle gun to a 4 to 5 inch group.
so be aware of what you are doing I know several people who normally shoot 3 or 4 inch groups and I can put there guns on my rest and shoot half of there normal group size. If you are a beginner and can find an experanced bench shooter ask him to show you the basics, it can make a big differance. Lee