TODAY I WAS GETTING GREAT VELOCITY from my 270 Win. 22inch Rem 700. Load: Barnes 130 TSX. MRP 61.0grs., Fed 215 primers,win. brass trimmed neck sized, velocity 3218 fps. Needless to say this is a smokin 270 winny load w/ no pressure signs. PROBLEM: 2 inch horizontal dispersion w 1/2 inch vertical variation.. Can someone give me generalized advise on horizontal groping and likely causes.. and cures .. much thanks Doc Stone

Wind, grip pressure, scope parallax (sp?)cheek weld,bedding...............

how fast you shoot and is it bedded?

if it where mine, i would check
1: OAL of the rounds
2: remove and remount scope mounts and scope rings
3: check ALL the screws
4: check bedding
5: check free floating of the barrel (does it change?)

I'll assume best practices on the shooters part, but how hot was the barrel and how many rounds/min

jeffe

I've got an AR10 that will spred it's shots across the target if I rest my cheek on the stock any more then a faint touching.
My Winchester 1886. off the rest, will spred it's shots if I touch the forarm with left hand.
Then there's occasions that evil spirits, grimlins are afoot and deviously move the bullets while in flight. How do I know? I know I had the sites lined up right so it had to be something other then me.
Jim

I have a new swarovski 6-18x50 scope on the gun for load development. It is mounted w/ leupold quick detachable rings. This is the first time I ever used this type ring.. I thought it would be convient for this scope as I will use it for load development then remove and move on to next rifle.. I also noticed that while rezeroing the load today to more nearly be cented on the target., the first shot was the widest right from the group.. This scope was also nearly maxed out to get enough elevaton when first mounted, so it is near its extreme range of extension for this rifle zero.. I throw out all these so you-all can give me more areas to check.. #1- rifle bedded and barrel floated. #2 shot slowly to allow barrel cooling #3-I don't know what cheek bedding is?? #4- shot off solid bench rest -type bags w/ pedestal. #5 OAL was .010 off the lands.. advise.. thanks much, Doc Stone

The most obvious question nobody has asked yet is does this rifle do this with other loads? If it does the problem is the rifle if not it's probably the load. Have you tried 60,60.5 and 61.5? I could be that this barrel has more sideways harmonics than vertical i.e. it vibrates left and right more than up and down. Sometimes cryo-ing can fix a little bit of these type gremlins.
It also may be goofy with the scope at the limits of it's adjustment. Model 700's are notorious for crooked scope mount holes. I have 1 that I can only use windage bases on because I don't own a scope with enough windage to keep it in the optical center. You could try reversing the scope bases to see if that helps you get nearer to center. I have a buddy that went through 6 sets of dual dovetail bases before he could find one that collimated.....DJ

With all due respect to DJ, don't try to flip the bases in this application. With the QD Leupolds on a model 700 there is only one right way to be installed. If you reverse the bases and rings, the recoil will act against the the QD levers and loosen the levers as you shoot. This is bad.

What also isn't good is being maxed out in ANY direction with your scopes adjustment. Seeing as you have it set up for QD's, mount up another scope which has more internal adjustment. The Swaro has 50 minutes of elevation adjustment (total travel) anything more than that would help.

Seating depth could be the issue, but less likely.

Finally, Remington beds their 700's with forend tip pressure for a reason. The reason being is that it works for them. Free floated may not be the answer for this rifle. Before you rebed it though, try shimming it to get tip pressure. See how it shoots.

Gabe

Thanks for the feedback. I have one load that seemed to have potiential before this horizontal stuff started. I'll go back to it and see if it will still group, if not then I am looking toward changing out the scope and mounts and try that.. again, thanks and I'll kepp you-all (a southern thing) posted., Doc Stone

As a very broad and general rule of thumb, horizontal dispersion is usually shooter related. Vertical dispersion is usually load related.

I usually shoot a load with a slight variation of propellant weight to see if that affects the dispersion. In your case I would try the identical load with a full grain less and half a grain less of propellant to see what, if any, difference it makes. THEN if the dispersion continues you can look into the other factors.

My first guess after that is the adjustment on the scope. I don't know the internals of yours but many times on a variable adjusted to the extreme of adjustment you will have strange things occur. Also, if yours has an AO for adjustment of parallax, you may not have it set for the range at which you are shooting and that is absolutely essential. Even a minor change of position of your eye relative to the scope will give you that dispersion.

Bob338, That Swaro does have an AO, good suggestion.
PapaScmud: As far as reversing levers go you possibly could be right, but Mauser 98 users have been reversing the levers to the right side on heavy caliber rifles for years. They have to because the bolt release gets in the way of the lever. I've never heard that recoil loosening the levers was an issue on them. It doesn't make sense to me that the small mass of a recoil lever would loosen if properly tightened, but then I've been wrong before . The Leupolds may be different but I doubt it.............DJ

fwiw--I remember trying some barnes xlc 185's in my 340 wby. This is a gun that shoots nice round groups with most anything else. At 300 yds I was getting about 1.5" vertical and 5" horizontal. It sure puzzled the hell out of me. Maybe I was doing it that day but, I put the blame on the "load". I think a load "combination" can do it but sure can't explain why. Just thought I'd complicate things by telling you my experience!!! Good luck. PS--I've had fine luck with the leo QR mounts on several rifles.

I just got half awake 3:00pm and suddenly realized what is probably the cause of my poor groups..The front pedestal rest w/ sandbag I use has a stop on the front so one can go back to the same place in the bags each time. With the rounded forend of the 270 I am probably not achieving the same exact amt of pressure and same exact contact on the front part of the gun each and every time and this stop restricts the barrel jump or whip differently on each shot, therefore horizontal and also some vertical spreading of group. Can someone direct me to a site or article about benchrest positions or technique.. Comments and advice needed as I shoot alone and isolated from good info.. thanks much , Doc Stone