6mmBR with Hodgdon BL-C(2) ... anyone using it?

[queen_stick]

I went to move a 1lb can of it out of my way, and noticed on the label it had a 6BR recipe... "interesting," I said out loud to myself.

I searched here and found one thread with almost no information, aside from a starting point - http://forum.accurateshooter.com/index.php/topic,1059718.msg9882813.html#msg9882813

I just found a sweet load for one of my 6Br's, so I might stop playing with that one for a while. However, my other 6BR (a hammer with 95gr VLD's and Varget) is going to be my "test rifle."

I will try the BL-C(2) with the Berger 95's and 105's, and the Sierra 107's and report my findings.
(I have a 28" Broughton, 8twist, 272nk, with the intention of sending the heavy bullets a long way out (1k yards))

I'm curious if anyone else has tried this and what kind of results you're finding?

 

[mbkmkk]

I would be curious on what your testing shows using BL-C. I am new to the 6BR and have some BL-C sitting around.

I did try IMR 4320 & AA2520 before going to RL-15, and they looked good.

 

[queen_stick]

Here it is in the burn-rate chart...

96 Accurate Arms 2520
97 Alliant Reloder 15
98 VihtaVuori N140
99 Hodgdon VARGET
100 IMR, Co IMR 4320
101 Winchester 748
102 Hodgdon BL-C(2) <----------------------
103 Hodgdon LEVEREVOLUTION
104 Hodgdon H380


mbkmkk, do you have any velocity numbers with IMR 4320 & AA2520 and the heavy bullets?

 

[cmillard]

there are many different burn rate charts. i have seen blc-2 listed as faster burning than varget and imr4895.

 

[queen_stick]

there are many different burn rate charts. i have seen blc-2 listed as faster burning than varget and imr4895.

Thanks Mr. Millard, I wasn't aware of that.

Do you happen to know why the order would change depending on which chart you look at??? Does it have to do with lot variations?

As a reference, here's where I got the chart... http://hodgdon.com/burn-rate.html

Walt

 

[ttfreestyle]

i tried bl-c2 when first testing my 6br. never shot as well as the varget, if memory serves it shot around half inch groups at 100 yards. just my experience

 

[queen_stick]

loaded one round each to simply look for pressure signs (I didn't even shoot at a target... just pointed in a safe direction)

Tulla SRM primers
105gr Amax seated long for a tight jam
Lapua brass

BLC2
29.0 gr ... no signs
29.5 gr ... very slight ejector mark (you really have to look for it, and catch the right light to see it) No cratering or flattened primer
30.0gr ... obvious ejector mark, primer cratered slightly (not to the point of blanking, just a slight lip) Primer not flattened.
(none of the loads caused stiff extraction. Bolt cycled perfectly)

outside temp was 80F when this was tested

======================

Based on what load info I could find, I figured I'd need to run it hot to get the velocity up on the heavy bullets.

Here are the combo's I tried, and the results...

These three components were constant:
Tulla SRM primers
Lapua brass
29.5gr BL-C(2)

I loaded 3x rounds of each bullet with the above three components:

Bullet and seating depth group size (3 shots @ 100yds) Avg Velocity
------------------------------------------------------------------------------------------------------------------------
Berger 95gr VLD (light jam) 0.125 2677
95gr Nosler Ballistc Tip (.010 jump) 0.556 2780
Berger 105gr VLD (light jam) 0.621 2658
Hornady 105gr Amax (light jam) 0.551 2724
Sierra 107gr MK (.010 jump) 0.310 2726

I know it's a small sample size, but I figured it would give a good idea what each combination will do.
All groups shot off a bipod and a rear bunny ear bag. I didn't have my flags out... I really should have
Groups were measured outside-to-outside, then subtracted .243.

This was definitely the top node for the 105's and 107's. For the 95's, the charge could come up a bit, but I don't know how much

Summary:

The 95Gr VLD's just hammered... my barrel seems to like them more than any other bullet I've tried. The 107 SMK's hammered as well, with 2 shots that measure .051, and the third went left to open the group up to .310 (that's why I should have had my wind flags out). I think the SMK's could pile into one hole with this load. The Berger 105's were in a straight vertical line. The Hornady and Nosler groups were all over the place, though they still shot sub-MOA at 100yds.

Tulla primers ... I don't like them so far. The velocity spreads were unacceptable for each group. For example, the berger 105's had a an ES of 160fps! I also had a couple "hang fires" (if that's what it's called) ... Pull the trigger, hear the click, then the bang. These primers haven't done that with other powders I tried, so maybe the combo of this powder and primer simply will not work? I don't know...

Bottom line is, I'll re-do the test with some CCI-450's and see how that changes things.

sorry for the wicked long post

 

[mbkmkk]

mbkmkk, do you have any velocity numbers with IMR 4320 & AA2520 and the heavy bullets?

No, I was just trying it for accuracy. I went to RL-15 only because thats what others recommend. IMR 4320 looked good.

 

[cmillard]

im sure there are a lot of factors as to why there are differences in the burn rate charts. there is a book on propellant profiles that might be of some assistence to you. sinclair international sells the book

 

[queen_stick]

im sure there are a lot of factors as to why there are differences in the burn rate charts. there is a book on propellant profiles that might be of some assistence to you. sinclair international sells the book

Thanks Cole... That book is definitely relative to my interests I think I'll pick it up!

 

[markr]

I have used BLC2 in several cartridges most notably 222 Mag and .308. In both cases it shot well after I switched to Magnum Primers! I prefer the Remington Magnum primers both large and small varieties.

 

[Laurie]

im sure there are a lot of factors as to why there are differences in the burn rate charts. there is a book on propellant profiles that might be of some assistence to you.

Cole,

the Profiles book is very good, but won't help here. Powder burn rate positions aren't fixed in stone is the issue - put a powder in different sized cartridges, different calibres, different bullet weight combinations and the relative burn rate may change. Some change more than others it seems, and that definitely applies to BL-C(2) / W748 (same thing, different labels).

The actual charge weights of BL-C(2) used in some cartridge / load combinations are often considerably larger than those that can safely be used by powders that are listed as slower burning in powder burn rate charts. That might suggest it becomes slower burning than they are in that cartridge / combination, or there may be another reason why it can use heavier charges and obtain higher MVs. I don't know which applies, but I do know that BL-C(2) is one of these odd propellants that you just have to look and see what it'll do in any particular application making it difficult to label. Over the years I've found it works very well in some things where I thought it wouldn't and not well where I expected it to do well - if that makes sense. The only common factor seems to be that it only performs properly on or near full pressure loads.

Ironically, the original Ball Lot C was a Winchester-Western made grade loaded into many millions of WW2 US manufactured 0.303" Mk7z cartridges for delivery to British forces somewhere, or maybe the UK. The war ended before delivery making the ammo surplus and Bruce Hodgdon bought it after the war and demilled the ammo, collecting and selling the contents. The powder sold well and after it was all gone, Winchester was contracted to make more, Lot C(2), or second variation. I don't know how close Lots C and C(2) turned out to be, but I never had any success loading it into .303" in the days when I shot Enfields and things. Moreover, despite all the conventional advice about using magnum primers with it, this created a terrible combination in the cartridge with low MVs, poor accuracy, and excess pressure signs. Trying this ammo in a Canadian straight-pull Ross M1910 rifle, the pressure spike was such that it caused a jacket failure on a 174gn Mk7 bullet copy, the core blowing out and disappearing down range, the jacket left as a cylinder in the throat and (luckily) stopping me chambering the next round.

Later on, I found it would perform very well with stiff loads under 185gn bullets in .308 Win back in the days when we thought that was a REALLY heavy bullet in the cartridge. Most people who'd tried it in .308 with 150s as they'd read it was very similar to the powder used in the US milspec M80 7.62mm cartridge thought it was a terrible performer and I picked up several part used cans very cheap as a result!

 

[cmillard]

i have been thinking about trying aa2520 or imr 4064 in my 6BR. i have attained some really nice velocity with 77 bergers and aa2520 out of my long range ar-15, so i might as well try it with my 6BR.

 

[queen_stick]

Cole... get out there and burn that powder! Let us know what you find out.

Laurie... Thanks for the interesting history on the powder. one thing I took out of your post is that I should try regular SR primers instead of the magnums. I have a couple different kinds of primers, so I'll try those too.

Not sure when I'll get back to testing with the BL-C(2)... I'm trying to get up to Williamsport this weekend... for the first time this year , so this week will be spent fine tuning a new load I want to try at 1K

hopefully next week I'll get to play with it some more... it seems there's not enough time in one day

 

[wapiti25]

The old surplus powder did look different from lot to lot, I don't have any experience with current mfg. the old h335 and Bl-c2 would show pressure very quickly when near the top, also was very sensitive to temp. It was dirty.

 

[wapiti25]

Queen - most burn rate work that I'm familar with is done in combustion bombs, which have a pressure limit at about 30,000 psi. The pressure is contained in the bomb until the test is over then the bomb is vented. When you get to 50 to 60 K as in the cartridge cases we use the propellants look different. The data from the bombs is a pressure Vs time ("Burn Rate") to a max pressure so the data reduction can be different depending on who is doing the work. Think about our cartridges when fired the volumne is constantly changing as the projectile is moving down the barrel, it's amazing to me when we want extreme spreads in the 10 ft/sec range

 

[markr]

In my experience with BL C2, it requires a magnum primer i.e. CCI SRM or Rem SRM preferably...for sure ignition, then it comes into it's own!

loaded one round each to simply look for pressure signs (I didn't even shoot at a target... just pointed in a safe direction)

Tulla SRM primers
105gr Amax seated long for a tight jam
Lapua brass

BLC2
29.0 gr ... no signs
29.5 gr ... very slight ejector mark (you really have to look for it, and catch the right light to see it) No cratering or flattened primer
30.0gr ... obvious ejector mark, primer cratered slightly (not to the point of blanking, just a slight lip) Primer not flattened.
(none of the loads caused stiff extraction. Bolt cycled perfectly)

outside temp was 80F when this was tested

======================

Based on what load info I could find, I figured I'd need to run it hot to get the velocity up on the heavy bullets.

Here are the combo's I tried, and the results...

These three components were constant:
Tulla SRM primers
Lapua brass
29.5gr BL-C(2)

I loaded 3x rounds of each bullet with the above three components:

Bullet and seating depth group size (3 shots @ 100yds) Avg Velocity
------------------------------------------------------------------------------------------------------------------------
Berger 95gr VLD (light jam) 0.125 2677
95gr Nosler Ballistc Tip (.010 jump) 0.556 2780
Berger 105gr VLD (light jam) 0.621 2658
Hornady 105gr Amax (light jam) 0.551 2724
Sierra 107gr MK (.010 jump) 0.310 2726

I know it's a small sample size, but I figured it would give a good idea what each combination will do.
All groups shot off a bipod and a rear bunny ear bag. I didn't have my flags out... I really should have
Groups were measured outside-to-outside, then subtracted .243.

This was definitely the top node for the 105's and 107's. For the 95's, the charge could come up a bit, but I don't know how much

Summary:

The 95Gr VLD's just hammered... my barrel seems to like them more than any other bullet I've tried. The 107 SMK's hammered as well, with 2 shots that measure .051, and the third went left to open the group up to .310 (that's why I should have had my wind flags out). I think the SMK's could pile into one hole with this load. The Berger 105's were in a straight vertical line. The Hornady and Nosler groups were all over the place, though they still shot sub-MOA at 100yds.

Tulla primers ... I don't like them so far. The velocity spreads were unacceptable for each group. For example, the berger 105's had a an ES of 160fps! I also had a couple "hang fires" (if that's what it's called) ... Pull the trigger, hear the click, then the bang. These primers haven't done that with other powders I tried, so maybe the combo of this powder and primer simply will not work? I don't know...

Bottom line is, I'll re-do the test with some CCI-450's and see how that changes things.

sorry for the wicked long post