2, 4, 6, 8 load variation

[Squirrel45]

Hi everyone

 

If one had say had 4 627s of different length barrels would a load that is accurate in 6" be accurate in 4" etc. I ask this because I have a scope on my 627 v comp and would like to use it to develop loads in 4" 627 that has a 10moa dot. I understand that velocity would be different, and SD, ES would also be somewhat off as well. However would the accuracy remain? 

 

Thanks

Squirrel 

[AzShooter]

With a dot I seriously doubt that you will see any difference in accuracy.  I use a 12 on both my 4 and 6 inch 617s and shoot the same with either.

[Toolguy]

Both guns will be equally accurate with a given ammo if they are both mechanically correct. If one gun has a bad crown, bad forcing cone, out of time, barrel constriction, etc., it won't be as accurate as one that doesn't have those problems. Barrel length doesn't matter much. Any length of barrel can shoot tight groups if everything is right.

[pskys2]

So many variables.

Suggestions:

1) take each gun and do some 25 yard groups from a rest with the same load.  Record the group size.

2) work up the most accurate load with a dot

3) test that load in each and see if it varies from step 1.  I.E. in step 1 your group with a dot was 2" and with iron sighted shorter barreled guns you went 2 1/2", 3" and 4" and with the newer loads you'd expect those variances to remain constant.

4) Or you can easily swap out the irons of any 627 with a Dot, and if you're careful you won't even change POI.  

[tim_w]

Things that come to mind that are revolver specific.  The variation in cylinder throat diameter and barrel groove diameter and the ratio and associative differences of the two between samples.

 

Rev 1:  0.3585 throat 0.3550 groove 0.005 cyl gap

Rev 2:  0.3580 throat 0.3585 groove 0.006 cyl gap

Rev 3:  0.3578 throat 0.3590 groove 0.009 cyl gap

Rev 4:  0.3595 throat  0.3560 groove  0.010 cyl gap

 

Different Revolver samples will work better or worse with different bullets based on diameter hardness etc..

 

All comes down to how tight S&W held the tolerences on those specific guns on the various days the parts were manf and then again on the day they were assembled.  Their tolerence spread  that makes it thru their QC system is something you could drive a truck thru.

 

Other effects like a barrel with a tight forcing cone groove diameter vs larger at the muzzle would effect all loads regardles same with damaged crowns ect.

 

 

[Toolguy]

Agree with tim_w. Every gun is an individual entity base on the parts it is made with. Every part has + or - tolerances. Some parts aren't made right. Depending on how the tolerances on that collection of parts stack up or cancel out, and what things aren't right, determines how that particular gun shoots, how good the action is, etc. The most consistent parts are the springs and MIM parts.