BLC-2 in the 223

[Hunter Customs]

As bullets get heavier, the slower powder comes into its own. But with 50-55 grain bullets the H335 is really more speed appropriate.

Unclenick,

As I said in my other post I certainly appreciate your thoughts, not only on this particular topic but on others you have taken the time to post to.
By the way I have read the article you gave links to three times, it's very interesting information.

In the above quote am I correct in assuming that your reference to the slower powder you are referring to BLC-2?
If that's the case my reloading manual list H335 as being slower then BLC-2, as a matter of fact they list BLC-2 and Win 748 as being the same in burn rate.

I know burn rate is not the end all to this subject but it amazes me the loads listed in my manuals for bullets as light as 40 grs for 223 using BLC-2.

I have contacted Hodgdons for their thoughts about secondary spikes with light bullets in 223 using BLC-2 but as for now they have not got back to me.

Again I want to thank you for your time and willingness to share your knowledge.

Best Regards
Bob Hunter

 

[603Country]

There was a thread a year or so on the forum that discussed secondary pressure spikes. That did worry me, so I spent a lot of time reading up on the subject. What I found made me feel a bit better. If you have a tight barrel (I do) and if it's 20 inches or shorter (mine is) then the problem should be less of a worry. If you want more info, then google away or ask Unclenick.

Also, I decided to save the BLC-2 for bullets heavier than the 40 gr Noslers I normally use. I also plan to eventually switch to Benchmark, which I think was recommended by Unclenick. And I probably should switch to SR Magnum primers with the H335, which I have not yet done.

And I can positively report that I have neither ringed my barrel, nor blown a chunk off the end of it. Yet...

 

[Hunter Customs]

603Country,

Thank you for your thoughts on this.

The rifles I worked the BLC-2 load up for are:

Armalite VSR 18 inch stainless steel barrel 1in8 twist 223 wylde chamber

DPMS re-build, Criterion chrome lined 20 inch HBAR barrel 1in8 twist 223 wylde chamber.

Savage 10/110 bolt gun 20 inch moly steel barrel 1in9 twist 223 chamber.

Bullets being used in this load are Sierra's 55gr Blitzking #1455.

I've never used any Benchmark, do you know if it meters as well as BLC-2 or H335 from a powder measure?

Thanks again for your time and thoughts.

Best Regards
Bob Hunter

 

[603Country]

From what I know, or think I know, you should be Ok with the 55 gr bullets and BLC-2. As for how Benchmark meters, I can't say, since I haven't bought any yet. Gotta burn some on-hand powders before I buy more, says the Wife.

And honestly, I'm so happy with the accuracy I get with H335, I may never really switch to Benchmark. I should try it however.

 

[jetinteriorguy]

Benchmark works well for me in the heavier bullets, but as far as metering through a powder measure weellll. I tried it through my Lee PPM, Lee Auto Drum, and my Lyman 55. The good old Lyman 55 was the clear winner here.
For the 55 gr bullets my go to powder is H335.

 

[Hunter Customs]

After doing some checking I believe Benchmark is an extruded powder so I don't believe it will throw consistent powder charges from my powder measure.
If I wanted to use an extruded powder and weigh each charge I might as well stay with IMR4320 as I have a good accurate load already worked up using it.

As for the secondary pressure spike issue it seems this takes place in factory loaded ammo also, so one may be ringing their barrel shooting factory ammo and not even know they are doing so.

I know the simple solution would be to purchase some H335 which I most likely will do when I purchase powder again.
However that means I'll have to work up new loads again and hope they shoot as well in all three rifles as my BLC-2 load does.

Plus all three rifles shoot Black Hills 52gr match, PMC Bronze 55gr FMJ and my BLC-2 load all to the same point of impact so I do not have to do any scope adjustment when changing loads, this may not be the case with H335.
Add to the fact that I still have the biggest part of an 8lb jug of BLC-2 that I'll really have no use for unless I choose to use heavier 223 bullets if this secondary spiking is that much of an issue.

Like 603Country I've been reading all I can find on the secondary spike issue, I've read so much my head is starting to hurt.
I've yet to hear from Hodgdon's on this subject I may have to give an old shooting buddy that works at Sierra bullet company a call, he's a ballistic tech for them and may be able to shed some light on this subject.

Again I thank everyone for their thoughts and comments.

Best Regards
Bob Hunter

 

[Ifishsum]

I have fired many thousands of 53-55gr bullets with BL-C(2) in my 20" ARs without any hint of barrel ringing or other adverse affects - of course that is anecdotal and NOT proof that it cannot happen - but I can tell you it isn't something I worry about and I did read up on the subject a couple years ago when I first saw it mentioned. FWIW I always use magnum primers with ball powders like BL-C(2), primarily because I found more consistent velocities after experimenting with both. Not sure if that might make any difference as far as the possible secondary spikes or not, but it's how I load.

I agree that H335 probably is a better choice for lighter 223 bullets but for a long time I simply couldn't find it anywhere and I already had an 8 pounder of BL-C(2) - plus I could also find more supply from time to time for that when H335 wasn't available to me. If you have the BL-C(2) and are hesitant to use it with 55s, I think a heavier bulk bullet like 62gr Varmageddon would be a good choice, as well as any of the 68-69gr offerings from Hornady or Sierra.

 

[Hunter Customs]

Thanks Ifishsum, I've pretty much came to the same conclusion as you and 603Country.

I'm sure there's many variables involved with the secondary spike issue but if it was that much of an issue I'm pretty sure Sierra and Hodgdon would no longer have it listed as a powder choice to use.

Best Regards
Bob Hunter

 

[Unclenick]

That assumes they would be aware of it. You can ring a barrel without affecting accuracy appreciably until it gets severe, and if you don't look with a borescope, you may decide it isn't there. Because the measured spike is actually a ripple in the steel traveling back from where the localized pressure spike actually occurs, and is not a pressure change at the chamber, it is not detected by either a copper crusher or a piezo transducer that samples chamber pressure. Only the strain gauge shows it because it is measuring expansion of the whole chamber as a pressure indicator and not directly measuring gas pressure. Strain gauges are not included as a method in the SAAMI standard. The transducer housings all ride the surface of the metal so that if it showed on them at all, it would appear as a dip in pressure from lifting the transducer body away from the pressure source momentarily.

When Charlie Sisk reported his experiments (either 24 Hour Camp Fire or THR; I've forgotten which) he said he did the muzzle blow-off demo for several industry persons and that they basically shrugged their shoulders and did nothing with the information. They felt the SAAMI standard covered their backsides, apparently, and that's all they were interested in. SAMMI doesn't address the visible-by-strain-gauge-only phenomena.

If that's the case my reloading manual list H335 as being slower then BLC-2, as a matter of fact they list BLC-2 and Win 748 as being the same in burn rate.

BL-C(2) being close to 748 is correct, but H335 being slower is not. If you look at all the different burn rate charts you find a lot of powders are ranked differently in different burn rate charts. Nobody's paying to measure all these powders, so I think they try to guess based on what cartridges they are commonly used in and what velocities they achieve with particular bullets with what charge weight.

That H335 is WC844 and BL-C(2) is WC846 is published in Hodgdon's 2009 MSDS. They may not know the burn rates for powders from other distributors very exactly, but for the ones they distribute they keep the buirn rate specifications for ordering purposes, so their burn rate chart will be the most accurate for the powders they distribute. It ranks BL-C(2) in position 104, next to 748, and H335 in position 82, next to Benchmark. A lower number is faster on their chart. QuickLOAD's powder data is based on vivacity bomb measurements of actual samples (though the tested lots may not match the target burn rate spec exactly). It gives BL-C(2) a burn rate in units of 1/bar-s of 0.5150, while H335 is at 0.6300, or about 22% faster.

The military specs ammunition not only as to a peak pressure upper limit but also has a required gas port pressure window and a tighter velocity tolerance than SAAMI uses for the same bullet weights, This is in order to keep existing guns operating and existing sight systems calibrated correctly. You can guess from their finding that WC846 was too slow for 5.56 that it probably raised the gas port pressure too high when the velocity was correct.

 

[Hunter Customs]

When Charlie Sisk reported his experiments (either 24 Hour Camp Fire or THR; I've forgotten which) he said he did the muzzle blow-off demo for several industry persons and that they basically shrugged their shoulders and did nothing with the information. They felt the SAAMI standard covered their backsides, apparently, and that's all they were interested in. SAMMI doesn't address the visible-by-strain-gauge-only phenomena.

Well I spoke with ballistic tech at Hodgdon this morning, his reply to my questions on secondary pressure spikes was that I was the first person that ever mentioned this to him. He also stated that with all the people using BLC-2 in 223 and other small rifle calibers shooting 55gr or lighter bullets if someone had damaged their barrel Hodgdon surely would have heard about it by now. Going by Charlie Sisk experience maybe, maybe not.

With all I've read I'm curious if there's others out there that's experienced secondary pressure spikes, if so what calibers and loads did these occur in, also were any of the loads factory ammo.

Best Regards
Bob Hunter

 

[603Country]

Regardless of what the Hodgdon tech says, I tend to believe that Charlie Sisk did indeed shorten a few barrels in a non-standard manner. Therefore, secondary pressure spikes exist. And I like shooting 40 gr bullets, and I have BLC-2 powder (which I don't much use). And I hate to worry over stuff like this. So, after much reading, I have come to believe that if I have a combination of the following, I should be Ok:

- 20 inch barrel, or shorter.
- nice tightly bored new high dollar barrel.
- good ignition of the powder (magnum primers), which is H335.
- use the BLC-2 with 55 gr bullets.

But, that's what I think. I don't know it to be fact.

 

[Hunter Customs]

I agree 603Country, I too believe Charlie Sisk blew off the ends of several barrels from secondary pressure spikes, I also believe that secondary pressure spikes exist even in factory produced ammo.

From what I gathered Charlie's experiments was with new barrels (I would like to know his load info) everything else I've read so far on the secondary pressure spike issue was using guns with very worn barrels.

I believe there may be a lot of variables involved with secondary pressure spikes, things like load data, barrel bore conditions, barrel length, maybe even atmospheric conditions should be taken into account and listed. To me secondary pressure spikes is something that should be tested more thoroughly so we in the shooting community can have a better understanding of the subject.

I also believe in what's been termed as double detonation in large volume cartridge cases (mainly handguns), but I know it seems to be hard to reproduce where as secondary pressure spikes is not.
Maybe I'm to curious, however I will continue reading everything I can find on secondary pressure spikes and hopefully end up with a better understanding on the subject.

Best Regards
Bob Hunter

 

[smarquez]

I used BLC2 behind a 69 gr. SMK and got really nice and consistent accuracy. 3/4" but a real shooter could probably get it a lot better.

JD Machines upper with a SS Black Hole Weaponry, 18" Wylde with rifle gas system.

 

[rodfac]

Bob, I use the exact same load in .222 Magnum, just about the same case as the .223. Rumor has it that the military used it for work up before deciding on the 5.56mm. At any rate, my little Sako L461 (that tiny one with the Mannlicher stock) will put 5 in a row in less than 1/2" at 100 yds with the Sierra or Hornady 52-53 gr Match bullets...Rod

 

[Unclenick]

Several points:

If you buy a Pressure Trace, you can simply see secondary spikes for yourself and decide if they appear significant. The article I linked to shows bad ones. Here's one I measured produced by slow WC852 in 150 grain 30-06 ball. You can see how small it is compared to the severe ones in the article.

Slow WC852 was the stuff that was loaded into M2 Ball at over 56 grains and that was disqualified for use in the M1 Garand because it raised gas port pressure too much. Fast WC852 only needed about 53 grains with the same bullet to get to the same velocity, so it had a combination of a higher peak and lower muzzle pressure.

You can see the pressure rise is smooth to about 30K when the bullet finally slammed into the throat and initiated a pressure wave in the barrel. That reflecting (running back and forth, up and down the barrel) pressure wave makes the rest of the curve lumpy. When the pressure drops to zero, you see double lumps for each cycle due, I suspect, to input protection diodes at the A to D converter interacting with input capacitance.

The small secondary spike bothers me not because it is significantly high, but because it is located about when the bullet would be 14" down the bore (from QuickLOAD calculation; WC852 is sold in canister grade as H380, which is the powder model I used, though H380 is like fast (normal) lot WC852, so I slowed it down a little). Plus, that lump is broad enough and not rapid, like the pressure wave, so I believe it to be a transverse wave. Transverse waves travel much more slowly than pressure waves (pressure waves are at the speed of sound in steel, which is about 17 times faster than in in air, which is why you see so many cycles of them in the plot). My point is the transverse wave needed time to get back to the chamber where the strain gauge is. This means the actual pressure event occurred even earlier. I'm sure this location varies with the powder choice and bullet weight. But it's not at 20" as RSI describes.

I found, as RSI did, that going either to a heavier bullet or to a faster powder always eliminates these spikes.

 

[Hunter Customs]

smarquez, thanks for your info. I don't really want to go to a heavier bullet because the 55 Blitzkings are working so well on the coyotes and they shoot the to the same POI as the other two loads I like to shoot in my rifles.

rodfac, thank you for your info and I think I may have told you this before, I sure like your by line about our flag, agree with it 100%.

Unclenick, thanks for the additional info and graph. I'm still reading all I can on the subject and you are correct that many seem to confuse secondary pressure spikes and detonation as being the same.

Best Regards
Bob Hunter