Lapua 139's jump or no?

[moosehunter]

Lapua 139\'s jump or no?

Im working up a load in my 6.5-284 with these bullets and Im at .6moa with a .025" jam. Now I want to play with the seating depth and tighten that up. How are you folks using these bullets?

 

[260shooter]

Re: Lapua 139\'s jump or no?

260 AI with 139's 10 thou into the lands and it hammers /ubbthreads/images/graemlins/wink.gif

 

[moosehunter]

Re: Lapua 139\'s jump or no?

Your about the first person to reply who runs these bullets into the lands. What accuracy are you getting at long range with that load? Ive run mine into the lands from .010" to .025" and at 200yds the best Ive got is .6moa with 5 shots. To be competive at 1K I need 1/4moa give or take.

 

[Fiftydriver]

Re: Lapua 139\'s jump or no?

Most match type bullets on average will shoot the most consistantly seated into the lands to some degree or at least touching. I would suspect this bullet will be the same.

25 thou into the lands is pretty deep unless your running lower neck tensions and the bullets are being seated by the lands when you chamber the round in the rifle. THis is also common practice with some BR shooters but you have to be careful not to run your neck tension to tight.

You do not want a serious preload on a bolt when you chamber a round. Even in a perfectly built rifle this is not desired so if your running your bullets that deep, I would hope your neck tensions are not overly tight to allow the bullet to be seated by the lands.

If it were me I would load then 5 thou into the lands to start with. This will just show a slight mark on the ogive from the lands. Start there and play around with it.

Kirby Allen(50)

 

[moosehunter]

Re: Lapua 139\'s jump or no?

Im at approx .002" tension I can feel them engage about half way down the bolt close then seat in. Once I hit that seat the ES and SD dropped but the accuracy can definatly be better.

 

[260shooter]

Re: Lapua 139\'s jump or no?

The rifle shoots 5-shot groups that hover around 1 inch at 300 yards. It is my Dad's F-Class rifle, I build the ammo and do initial testing (but have never shot it at 1K, I spot his shots and know how the rifle preforms).We just switched to 139's so I knew I had to find the sweet spot for this bullet. I loaded one powder charge and four different seating depths five rounds each (base to ogive)

3.280 velocity 2947 ES 23

3.275 velocity 2959 ES 14

3.270 velocity 3011 ES 81

3.265 velocity 2868 ES 22

Took the 3.275 load and fired an 8-shot 100 yard group of .424 with an ES of 16 fps. We took the load and shot a 1000 yard match and the load held X-ring for vertical, had a switching wind so our scores sucked but the rifles preformed great. A 1/2 MOA rifle will win matches if the shooter can read wind (therein lies the secret to LR shooting /ubbthreads/images/graemlins/laugh.gif)

260

 

[moosehunter]

Re: Lapua 139\'s jump or no?

Just finished testing with .005" to .025" off in .005" increments. First thing noticed was a velocity and pressure drop. The next thing was my 3 shot groups went ot .3 and .4moa at 200yds. Best was a .3 average with .005" off but the ES and SD was higher than I would like. Next best was .015" with an average of .4moa with ES of 14 and SD of 6. Figure now I'll work with that and up the charge in .3gr. to see if it sweetens the groups any.