JLK 6mm 105 Bullets

[dbduff]

Thanks for the info. I am using the Alex Wheeler method to find "touch" with the bullet which is very close to what you described. What I am most interested in is the group info and at what seating depth you maxed out at. Also how much groups changed with "X" adjustment. Thanks again.

Ed

3 inch at 3oo to 3/4”, 3 shot groups. I use Wheeler method as well but it is not where the rifling will seat your bullet in the case. I was about .008 beyond where the Wheeler method said I was, or to put it another way, where the best, (at the moment) accuracy with that bullet was. To simplify, find your touch point using the Wheeler method, then lengthen out your base to olgive number by .003 for 3 shot groups. Bet you see improvement in .008-.010 “. If you go that way, be sure to measure your ultimate “best” length because it may not be what your .003 steps add up to because the rifling gets in the way and puts the bullet where it wants. Make a dummy round to that measured length and chamber to make sure the bullet will stay in the case if you need to extract. Ymmv. Good luck.

 

[efoleyjr]

3 inch at 3oo to 3/4”, 3 shot groups. I use Wheeler method as well but it is not where the rifling will seat your bullet in the case. I was about .008 beyond where the Wheeler method said I was, or to put it another way, where the best, (at the moment) accuracy with that bullet was. To simplify, find your touch point using the Wheeler method, then lengthen out your base to olgive number by .003 for 3 shot groups. Bet you see improvement in .008-.010 “. If you go that way, be sure to measure your ultimate “best” length because it may not be what your .003 steps add up to because the rifling gets in the way and puts the bullet where it wants. Make a dummy round to that measured length and chamber to make sure the bullet will stay in the case if you need to extract. Ymmv. Good luck.

So what you are saying is if I seat for 0.008" into the lands when I chamber the round it may get pushed back to where it measures 0.003" into the lands. If so, do you load to 0.003" or continue to load to 0.008"? Or are you making the dummy just to see if it can be extracted without pulling the bullet from the case? Thanks

Ed

 

[dbduff]

So what you are saying is if I seat for 0.008" into the lands when I chamber the round it may get pushed back to where it measures 0.003" into the lands. If so, do you load to 0.003" or continue to load to 0.008"? Or are you making the dummy just to see if it can be extracted without pulling the bullet from the case? Thanks

Ed

I would load to the .003, not the .008. The dummy round will tell you if you can successfully extract it at 003. That may also vary depending on how tight or loose your neck tension is. None of this is gospel, simply what I’m doing that worked this weekend. Good luck.
D

 

[efoleyjr]

Thanks. I will give it a try.

Ed

 

[BIG D]

Update on seating test with the 105 JLK. I played around with neck tension. And I’m using my expander button in my dies. I’m using right at .001 neck ensign. Seating force is right at 18 on 21st century hydro arbor press. I also opened my chambers neck dimension up to .272 with my 6br reamer (Brx reamer is .2705). I feel I wa getting inconsistent release because this is non turned brass. I loaded up my standard 33.30 varget load and went and tested seating at -.010, -.040, -.080 and -.120 The Berger vld way of testing. Prior testing showed mixed results going from +.015 out to -.045. I would get decent groups but not consistently. The Berger vld way showed wild es/sd at -.010 but a decent group at 300. -.040 showed good es/sd and a decent round group. So I retested both -.010 and -.040. -.040 was definitely the clear winner with more consistent groups and single digit es/sd numbers. So I played both sides of -.040 with -.035, -.040 and -.045. -.040 was just the best out of these. I then took my powder charge and loaded 33.10, 33.30 and 33.50 at -.040 and tested each. 33.1 was definitely out of the node be the poi was lower on the target. 33.30 and 33.50 were so close I couldn’t decide what was better. The speeds were 3050 for the 33.30 and 3060 for 33.50. Single digi es/sd for both. the weather here was upper 40s with 10 mph wind. If it was 70-80 degrees I’d feel inclined to just load 33.40 and call it good. But I see no reason to load it with more powder right now. I think opening the chamber neck is the best thing I’ve done with this rifle. Speeds and groups show basically the same results. The fast shots go high and slow ones go low. I couldn’t get that before and it would make me scratch my head. This one is going to run this 33.30 -.040 load until it’s toast. But looking how nice it is outside today I may test with other primers. But idk if I can hold tight enough off bipod to improve on these results. Using the little one inch orange target dots I can keep them all in the orange at 300 yards. In all fairness I can’t hold any tighter or the groups would shrink. I’ll work on that next. Less pop more water!

 

[efoleyjr]

Update on seating test with the 105 JLK. I played around with neck tension. And I’m using my expander button in my dies. I’m using right at .001 neck ensign. Seating force is right at 18 on 21st century hydro arbor press. I also opened my chambers neck dimension up to .272 with my 6br reamer (Brx reamer is .2705). I feel I wa getting inconsistent release because this is non turned brass. I loaded up my standard 33.30 varget load and went and tested seating at -.010, -.040, -.080 and -.120 The Berger vld way of testing. Prior testing showed mixed results going from +.015 out to -.045. I would get decent groups but not consistently. The Berger vld way showed wild es/sd at -.010 but a decent group at 300. -.040 showed good es/sd and a decent round group. So I retested both -.010 and -.040. -.040 was definitely the clear winner with more consistent groups and single digit es/sd numbers. So I played both sides of -.040 with -.035, -.040 and -.045. -.040 was just the best out of these. I then took my powder charge and loaded 33.10, 33.30 and 33.50 at -.040 and tested each. 33.1 was definitely out of the node be the poi was lower on the target. 33.30 and 33.50 were so close I couldn’t decide what was better. The speeds were 3050 for the 33.30 and 3060 for 33.50. Single digi es/sd for both. the weather here was upper 40s with 10 mph wind. If it was 70-80 degrees I’d feel inclined to just load 33.40 and call it good. But I see no reason to load it with more powder right now. I think opening the chamber neck is the best thing I’ve done with this rifle. Speeds and groups show basically the same results. The fast shots go high and slow ones go low. I couldn’t get that before and it would make me scratch my head. This one is going to run this 33.30 -.040 load until it’s toast. But looking how nice it is outside today I may test with other primers. But idk if I can hold tight enough off bipod to improve on these results. Using the little one inch orange target dots I can keep them all in the orange at 300 yards. In all fairness I can’t hold any tighter or the groups would shrink. I’ll work on that next. Less pop more water!

BigD,
Did you compare the 0.040" jump load to say a 0.003-0.008" jam load? "dbduff" is saying his gun shoots better with the jam loads. Go figure, this reloading thing can drive you nuts.

Ed

 

[BIG D]

BigD,
Did you compare the 0.040" jump load to say a 0.003-0.008" jam load? "dbduff" is saying his gun shoots better with the jam loads. Go figure, this reloading thing can drive you nuts.

Ed

Yes I did. I didnt Try jam after lightening up on neck tension. I guess I could go try that today. I’ve never had any luck jamming. So I think I will just run this load. It’s shooting one hole groups at 100 yards. If I’d Measure I’m sure they would average in the .2s. At 300 it hangs inside 1” pretty well for 5 shot groups. Some are less then 1/2”. So for a barrel with 1,000 rounds fare a setback at 700 ish as a 243 Winchester I don’t think I can ask for much more. I don’t want to waste components as my varget supply may not get me through the summer.

 

[highdrum]

What bc you guys running on these? jlk stars 540 g1, which equates to 270 g7 to get same drop at 1k.