After sighting in a brand new rifle I started working up loads. Shooting a CZ550 American in .270. I used H4831 and Hornady 130gr Interbonds. I worked up my loads from 58 gr to 60 gr.of H4831. I was very dissappointed in the beginning. The first shots for each group were spot on every single time. I then got vertical stringing initially and then to the right about an inch shooting the loads from 58, 58.5, 59, 59.5 grains of powder. [Careful research on this forum tells me the barrel is getting warm and touching the stock most likely pushing the round off.} Well, off to the gunsmith I will go I think for some stock relieving and bedding. It was shooting like a shot gun and I couldn't get better than 3 inch groups to save my life, some 6 inch groups....until I got to 60 grains of H4831! Its like a new day dawned. And while I didn't get one single small minute group...the group tightened dramatically. BUT I have TWO separate groups. Using 6 shots, waiting about 5 mins between each shot I have two separate groups about two inches apart and about 1 inch in diameter for each group. Can someone please tell me what is causing this? What can I do about this? Thanks for everyone's help.

Am I right in assuming you have NOT done anything to the bedding or barrel channel yet?

Yes, you are right. I haven't bedded the rifle or done anything to the barrel channel. When I reached the 60gr load of H4831 for this bullet [Hornady Book says I can go to 62gr] the groups shrank to 1 inch, but instead of vertical stringing I got two seperate groups about 2 inches apart. I gather this is the harmonics in the barrel. But was wondering if it could be something else, something I can talk to the gunsmith about and have done.

SWMO? Well...I spent the better part of my 1st 20 years in Spfld. My immediate family still lives in that area.

Horizontal spread like you describe is often found to be a bedding problem - by all measns, have your 'smith go over the bedding and touch it up as he thinks fit.

Two distinct groups in either vertical or horizontal directions is often reticle float in the scope. If a bedding touchup doesn't fix it, you might want to try different glass.

It sounds like you've found the ballpark in which your CZ will really shoot-find and fix your problem and I think you'll have a damned fine rifle on your hands.

Yeah, it could be bedding or scope. You'll have to eliminate one possibility at a time. If you have a spare scope, that would be quick to check. If it's not the scope try free floating the barrel. That you could do yourself fairly quickly. If that doesn't work, it's back to plan A.

Scope rings are tight, right.

Scope rings are tight and the scope is a brand spanking new Leupold 3.5X10X50. I know that a new scope can have issues, so if the bedding and all else fails I will go to that plan. I will also go back one more time to check everything over including action to stock bolts torque. THank you for giving me ideas to check on.

I have seen brand new scopes be broken-especially Leupolds. I would swap that before the bedding, assuming you have another one you can swap. At least that would be free for you to try.

Renagade,

Like the others have said; I'd check the barrel channel bedding first, easily done by:

1. Applying a slight twisting motion (not trying to break the forearms off) with some pressure on the forearm. You may feel the forearm slopping around and the barrel moving in the Channel. Try doing similar with your finger pushing upwards on the barrel from underneath the forearm tip. Does the barrel go back to the same position every time?

2. Attempting to slip various thicknesses of paper between the barrel and the stock's forearm channel. You'll see imediately where the paper hangs up. Intitially try to slip a piece of papaper at a spot in the middle of the barrel channel since there my be some inbuilt upwards pressure at the forearm end (this may also be the cause of your two distinct groups).

3. Take a look around the action area noticing if the action scerews are tight, does it appear to be seated correctly? Does it move in this area when pressure is applied (from any angle, up down, backwards, forwards? Does the action spring/jump out of it's recess when unscrewing the action screws.

4.. Make sure both action screws (front & rear), are NOT TOO LONG.

All of this won't costya a dime - if any of the above is noticable a "Smith" can recommend a fix for you.

Dicking around with mounting and remounting scopes is personally NOT where I'd initially start.

i've gotten to a point that i bed every rifle before i even shoot it. only takes a few minutes