Help with load analysis (6BR, 80GR Berger FB, N135)

[Poor Shot 65]

Hi

I just rebarreled my 6mmBR and I am looking for help in determining the load to use.

Barrel is a Krieger LV 8 twist chambered with a .60 free bore.

Shooting 80GR Berger FB bullets. Bullets have been seated .015 jammed.

Powder is N135

Targets are at 100 yards. Each square of the target (I believe) is 1”.

At the start of this session, the barrel had 20 rounds shot through it.

Please see all the attachments for target info and raw numbers (speed, SD, ES etc). As my handle says, I am not a great shot, but im looking for a little direction here (stick with N135 ? which charges look good ? direction to go with seating etc ? or just give up :> ?) .

Looks to me that there are two possible nodes:

29 to 29.3 or 31 to 31.4 .. nothing looked really good though.

at 32 I saw signs of pressure - so im not comfortable going above 31.7 at this point in time.

Thanks

Adam

 

[urbanrifleman]

Do a seating depth test. I think they shoot best jumped.

 

[urbanrifleman]

Take 29.3 and do a test at
20 in
10 in
5 in
5 out
10 out
20 out
30 out

Do it twice or even three times. One will shoot the best.

 

[Poor Shot 65]

Take 29.3 and do a test at
20 in
10 in
5 in
5 out
10 out
20 out
30 out

Do it twice or even three times. One will shoot the best.

Sure thing. I will try to get that done this Friday. Thank you for the suggestion.

 

[urbanrifleman]

Sure thing. I will try to get that done this Friday. Thank you for the suggestion.

Please post your results. I am doing a workup with Ar Comp in 6bra and 1-7.5 Brux this week also.

 

[urbanrifleman]

Try this

Make fire rounds in three bags. 15 shots total. At that 29.3 load. Take one bag and put it in a insulated cup with with ice covered in salt.

Take another bag and put it in the oven at 130 degrees. Place in another cup with a heat pack.

Take all three to the range and shoot them over the chronograph.

 

[gunsandgunsmithing]

Go straight to imr 8208...about 31.5 grains and work from there. You'll probably find sweetness around 32.0. IME, from light touch to about .015 jam is the sweet spot for seating depth. Benchmark is another good choice. N135 can work but it's not the powder that I thought it would be in that combo. YMMV in that regard as it should be a good choice, if you judge by burn rate alone.

 

[urbanrifleman]

Go straight to imr 8208...about 31.5 grains and work from there. You'll probably find sweetness around 32.0. IME, from light touch to about .015 jam is the sweet spot for seating depth. Benchmark is another good choice. N135 can work but it's not the powder that I thought it would be in that combo. YMMV in that regard as it should be a good choice, if you judge by burn rate alone.

Interesting. I have never gotten them to shoot consistently jammed.

 

[Poor Shot 65]

Absolutely - I will keep on posing my results on load development for this rifle. I also have to do load development on a sako-trg 6.5 creedmoor as well .. th

Try this

Make fire rounds in three bags. 15 shots total. At that 29.3 load. Take one bag and put it in a insulated cup with with ice covered in salt.

Take another bag and put it in the oven at 130 degrees. Place in another cup with a heat pack.

Take all three to the range and shoot them over the chronograph.

I live in Henderson (next to Vegas)... so i am basically already shooting in an oven

Thanks

Adam

 

[swadiver]

jam 'em .015", if 30 grs of N135 doesn't work, try 32.2 grs. works great for me either load with the 80's in a 12 twist Brux 6BR.

 

[swadiver]

80 Bergers with two groups of 68 Bergers as well. all 5 shots at 100. 29.9, 32.0 and 32.2 grs of N135 with the 80s.

 

[Poor Shot 65]

80 Bergers with two groups of 68 Bergers as well. all 5 shots at 100. 29.9, 32.0 and 32.2 grs of N135 with the 80s.View attachment 1125749

Any idea of what the speeds were of the 80s ?

 

[gunsandgunsmithing]

Interesting. I have never gotten them to shoot consistently jammed.

I very rarely find jumping to provide best accuracy, with anything. YMMV.

 

[swadiver]

let me check to see if i

Any idea of what the speeds were of the 80s ?

let me check and see if i chrono-ed them

 

[KMart]

Go straight to imr 8208...about 31.5 grains and work from there. You'll probably find sweetness around 32.0. IME, from light touch to about .015 jam is the sweet spot for seating depth. Benchmark is another good choice. N135 can work but it's not the powder that I thought it would be in that combo. YMMV in that regard as it should be a good choice, if you judge by burn rate alone.

I agree with Mike and 8208. Light jam. Another combo that with the 80's that worked well was about 30 gr of LT-32 and a light jam. If I remember correctly the velocity with both was around 3150.

You need to do a seating depth test between touch and .015. It is really amazing how much .003" change in seating can improve groups.

 

[urbanrifleman]

I very rarely find jumping to provide best accuracy, with anything. YMMV.

Well if he does that seating depth test I told him to do I guess we will find out!!

 

[gunsandgunsmithing]

Well if he does that seating depth test I told him to do I guess we will find out!!

YMMV!! Do what works for you.

 

[SS GO DEVIL]

30.5 Varget and Jam .010.
3130 FPS. Bughole all day and low sd.
1:8 Twist Krieger No turn neck

 

[JFrank]

Hi

I just rebarreled my 6mmBR and I am looking for help in determining the load to use.

Barrel is a Krieger LV 8 twist chambered with a .60 free bore.

Shooting 80GR Berger FB bullets. Bullets have been seated .015 jammed.

Powder is N135

Targets are at 100 yards. Each square of the target (I believe) is 1”.

At the start of this session, the barrel had 20 rounds shot through it.

Please see all the attachments for target info and raw numbers (speed, SD, ES etc). As my handle says, I am not a great shot, but im looking for a little direction here (stick with N135 ? which charges look good ? direction to go with seating etc ? or just give up :> ?) .

Looks to me that there are two possible nodes:

29 to 29.3 or 31 to 31.4 .. nothing looked really good though.

at 32 I saw signs of pressure - so im not comfortable going above 31.7 at this point in time.

Thanks

Adam

This is Somewhat of an OCW test but in a vertical format whereas I’m only looking at the location of impact and not concerned about the shape of the groups. With that in mind 29.3 area appears to be decent place to start a seating test OR I could go up to the bottom of the next node for a seating comparison. ( shot #5)
But what do I know.....

 

[swadiver]

Any idea of what the speeds were of the 80s ?

approx. 3115 fps from a 24 inch barrel that was the 29.9 gr load. didn't chrono the 32.2 load