300 Yard 308 118gr Results

[APGE]

Hi Folks,

First trip to the range with a 17 twist 308 I had built for with no real serious purpose, but a bit of fun. Shooting 118gr BIBs using H322, 28" bartlien HV on a blueprinted remington.

Im a little stuck as to what load to work on.

All six of these groups have 3 good shots with a fourth blowing the group to 1-1.25". I was dealing with an unusual amount of mirage for the time of day (early morning), but if I waited around for good conditions where I live I simply wouldn't be doing any shooting. 47.8gr looks good, but the total lack of vertical in 48.7gr has my attention. Could I tune the horizontal with seating depth adjustments?

And advice on where to head from here? This gun probably wont see much action past 200 yards due to the 17 twist and 118gr projectiles, but it might get pulled out for the odd 600 yard, calm day shoot if it end up being an accurate rifle.

I definitely can't go hotter (these were in the 3450+fps range) and lower charges aren't worth posting pics of.

Thanking you,

 

[nso123]

I would start adjusting the seating depth on that 48.7 load. Maybe load a little on each side of that charge as well.

 

[ckaberna]

To big of increments, .3 in that case is big. Try loading .1 charge from 48.3- 48.9 then seating test
IMHO

 

[pilot]

You should be able to shoot heavier cast bullets in that rifle.

 

[joshb]

I would start adjusting the seating depth on that 48.7 load. Maybe load a little on each side of that charge as well.

This!

 

[APGE]

I would start adjusting the seating depth on that 48.7 load. Maybe load a little on each side of that charge as well.

So maybe try 0.1 and 0.2gr either side of 48.7gr? Seating depth is currently a 20 thou jam, so I'm thinking I'll then work back in 4 thou increments?

 

[michaeljp65]

what powder are you using?

 

[nso123]

Like suggested above, I would probably do some .1 grain increments from that 48.4 to around 48.9 to see if anything stands out. You can start a bar fight discussing how to adjust the jump. The Berger method moves it by .030 and .040 at a time and seems kind of big moves to me. I move .05 at a time and then work from there to get exactly what I want.

 

[APGE]

what powder are you using?

H322

 

[T-shooter]

To finalize a load, you should shoot probably 15-20. When you are getting close 10 of each will work. Watch the barrel temperature and shoot a couple warmup shots before trying groups. Like nso123 said, work your seating depths to try and tighten the groups after you've got the power load finalized. This is an old test with 168g .308's at 100 yards. It was shot round robin. My rifle like to be seated .025" off the lands for most bullets. These dots are slightly under 1" diameter.

This was shot at 215 yards with a cleaned and cold bore. The 1st shot was the low one and the last was the upper right, no cooling in between shots.

You can be fooled shooting just a few shots at a time. These 6 were shot at 215 yards all aimed at the center. I have no idea in what order. If only 2 shots were fired and they touched, you may think it was good, yet again, all 6 are in nearly a 2" circle.

 

[Murray Brook]

Is there a reason not to work with the 47.8 gr load??

 

[joshb]

Have you tried Speer TNT 125 grain?
They’re short for thier weight and cheaper than the customs. I’m waiting for the weather to warm up to try them in my new 30x 47. Guys here have mentioned that they shoot pretty well.

 

[Howland]

Take this with a grain of salt considering that I'm just starting down the long range path and don't know from experience - and if someone does know from experience, please chime in - but wouldn't the dispersion caused by an "unusual amount of mirage" be more horizontal than vertical? I wouldn't completely discount the 47.8 group, but I would focus on the 48.7 charge weight. This might be one of those occasions when seating depth testing makes sense with both charge weights.

 

[Bc'z]

Take this with a grain of salt considering that I'm just starting down the long range path and don't know from experience - and if someone does know from experience, please chime in - but wouldn't the dispersion caused by an "unusual amount of mirage" be more horizontal than vertical? I wouldn't completely discount the 47.8 group, but I would focus on the 48.7 charge weight. This might be one of those occasions when seating depth testing makes sense with both charge weights.

^^^^^^^^^^YES^^^^^^^^^^^