Think iv solved my accuracy problem

[shrek]

Picked up my 223 the other day, a second hand SSR-15 straight pull, very good condition, hardly been fired, 1-9 twist and the bore is like a mirror, just what i was after, so onto load devepolment.

 

however, as i started shooting for group i noticed erratic differences in shot placement on the target, and no apparent grouping showing straight off.

 

So i cleaned the bore and then tried again inbetween work, and still the same erratic shots (by erratic i mean one group could be at about 11 a clock and the next group say an extra grain of powder 4 inches low to 5 o clock,

 

By this point i thought id baught a dog of a rifle, then the lightbulb in my head switched on when i noticed the threads on the mod where longer than the rifle threading, and thy where starting to carbon up inside the mod, so ive drawn a picture on paint ( im just a big kid really) as to what iv found

 

I tried a 3 shot group with the mod off and it cloverleafed, so the moderator was in the lathe thisafternoon and i tapered off the threads which wernt doing anything but adding weight, my thoery being that gas was blasting out of the muzzle and creating uneven pressure waves through the mod as it bounced of the threads, unsettling the bullet, i tried a quick 3 shots out the back field to see if it had made a difference, and it looked promicing anyway

[Ronin]

Willie

 

 

the next book you buy should be "Rifle Accuracy, the Facts" by Harold Vaughn - excellent read, yoy appear to have worked out for yourself that irregular gas flow and interupted flow of the shock wave in front and behind the bullet WILL affect accuracy.

 

 

Exactly the same effect as a damaged crown

 

[Andrew]

You can tell the difference between a US shooter and a UK shooter in this tale; A US shooter would have pulled "that thing" off of the barrel and shot it after the first couple of bad groups! Being relatively unaccustomed to moderators we would have cast the evil eye in it's direction right off. ~Andrew

[shrek]

This is the first one i have ever baught my others are all made by myself to suit a particular firearm, and iv never had a problem like this before thats why it took me so long to think it would be the moddy!

 

Problem is now iv run out of 55gr v-max bullet heads, so need to go and find some, but im tied up all week draining fields