Trail Boss for subsonic? [Archive] - Home of the 6.8 SPC -

: Trail Boss for subsonic?

12-20-2010, 09:14 PM
I've used trail boss for light loads in my standard calibers, I noticed that it was easy to get low velocity when using it, however they were bolt action rifles. has anyone tried it in 6.8? If so what were results? Would it run or single shot only?

12-24-2010, 06:13 PM
Must be the holidays as HTR is the leader in sub loads. Probably post something on this after the holidays but I want to say that most of the loads I think he has talked about do not cycle. But he has some that do so he will have to clarify.

John A.
12-24-2010, 09:35 PM
I would very much like to get some recipe's for a good subsonic load. Whether they cycled or not, but cycling would be a plus in a semi-auto.

12-30-2010, 12:15 PM
Last I asked him, a 1:9.5 twist was his suggestion. I thought I'd find an old spec one for cheap.

They are like $275 at M1S which is WAY more than I wanna pay, not to mention the thread is 1/2 x 36 and IIRC a .308 Sandstorm can I have is 5/8 x 24

01-09-2011, 11:08 PM
The trail boss is bulky and really quiet, but it will not cycle. The IMR 4759 usually will. Check out this video done with the 308!

01-09-2011, 11:58 PM
Here is the current state of my testing and I will offer some loads, with the caveat that sub loads are a little bit of science, and a little bit of black magic. Use any of these loads at your own risk, and please work DOWN to these loads to avoid a stuck bullet or problems with positional charge combustion sensitivity.

IMO, Trail Boss is the best subsonic-load powder on the planet, if you don't really care about cycling. I have gotten the gun to cycle, but I've all but given up chasing the cycling AR-15 sub load. I want to be able to load the 150 and 160 grain bullets out to the proper place in the case mouth, and that just cannot be done with the AR-15 mag length restriction. You end up with problems like the 135 SMK being too far down in the case and the ogive sitting at the mouth, then the bullet not well supported, ergo tons of runout. It happens with the 150 SGK and the 160 NP, and unless you cut the lead tip off, you cannot get them into the mag and still support the bullet properly.

I used to think that you could carry around a mag full of subs and that we'd finally get a load that would cycle the action on any 6.8, even without enlarging the port or using a JP low mass carrier. I tried IMR 4759, reloder 19, 15 and even accurate #9, but none of them reliably cycled more than 1 gun (and that is 1:9.5 twist, eroded SAAMI chamber & a Paladin 3 position gas block with the port drilled out to .100"). I finally just got a .300 whisper / BLK and decided to build a super light little toy gun out of a Plum Crazy lower, and the Bushmaster carbon 15 upper receiver. With a 9" barrel, it will weigh about 4 lbs. and shoot the 240 SMK at 1050 FPS. That will be the cycling subsonic AR I carry. It works every time, and the loads are super easy, using .223 brass.

With my bolt gun, I have the freedom to load subs out to 2.4" and get the case mouth to ogive relationship right for those huge bullets. That gives me some tremendous accuracy.

Here are my best so far:

-130 BST
-7.2 grains Trail Boss
-2.305" OAL
-SSA brass
-Wolf SRM
-1080 FPS, and 1.4" group at 100 yards.

-140 Hawk
-7.6 grains Trail Boss
-2.155" OAL (these bullets are round nosed and the shoulder is the tip, so they hit the edge of the forcing cone, and disallow chambering if loaded any longer. They will not feed in an AR anyway.
- SSA / CCI 41
- 1095 FPS, about 2" group at 100

-150 SGK, with tips cut off
- 7.8 grains Trail Boss
- 2.305" OAL
- SSA / CCI 41
- only 999 FPS, but 1" group at 100 yards. Good BC on this bullet. Works great in my bolt gun or in the AR, but of course, does not cycle it.

- 150 Hornady Spire Point
- 7.8 grains Trail Boss
- 2.355" OAL (bolt gun only)
- SSA / CCI 41
- 1010 FPS, and the bullet seats right at the cannelure...beautiful. This is the best group I've seen yet, three bullets touching at 100 yards. The 4th and 5th shots were well within one inch of that group.

- 160 Nosler Partition, with tips cut off
- 10.8 grains of IMR 4759 SR (bulky but case capacity is at the low end of my comfort range, with anything smaller than the 160 NP...note: I refuse to use a filler)
- 2.305" OAL
- SSA / CCI 41
- cycles with can on but not off, most of the time, but does not lock mag back on my gun
- 1075 FPS, did not group these.

I shot some with reloder 15, W748, and 4198, but I was not that happy with the overall performance, so I went back to Trail Boss, and the bolt gun.

01-10-2011, 12:05 AM
HTR- if you want the rest of those 140's let me know I think I have 100-200 or so left... once I couldnt get them to feed and they didnt do what i wanted them to do I gave up on em.

01-10-2011, 12:35 AM
Thanks much for the offer, A, but I think I will stick with the spitzers, since I have had such good luck with them.

01-10-2011, 12:44 AM
Question? "Mixing" is a no-no (given)....using "Smokeless Powder" in a BP rig is a no-no (given). However? Has anyone tinkered with using some of the new BP Substitute for sub-sonic loads? Hodgdon's 777 comes in various grades of "fineness". It's pressures are about 15% HIGHER than real BP... and, it's FAR less corrosive than BP.

I have no idea if modern primers are too hot for BP use... but, BP is more of a "PUSH" (recoil) than modern's "SLAP". Wasn't the original .45-70 a .45 cal bullet infront of 70gr. of black powder? Would a feller be able to get full charges into the case with the sought after slower muzzle velocity?

A bolt action rig would be a GOOD test platform for load development with a chrono. The reason I bring it up is... guys doing the cowboy shooting are converting BP revolvers to use modern cartridges and like the Trail Boss loads for the compatibility. It seems to me that the desire to return to sub-sonic velocities would be a good reason to look at BP Substitutes.

BP guns like to have a little compression to fuction well. The label on my "777" (fffg) lists a .45 cal lead round ball with 35gr of powder, lit by a CCI #11 primer pushing along at 987 fps. Additionally, as a side note... BP is "measured" by volume, so, it may "weigh" different when put on a scale from a powder measure.

The recent mentions of "Trail Boss" got me to wondering.

01-10-2011, 12:50 AM
Thanks much for the offer, A, but I think I will stick with the spitzers, since I have had such good luck with them.

No worries, I will figure out something to do with them, Have you gotten to kill any pigs with one? wondering how they did.

01-10-2011, 07:20 PM
No worries, I will figure out something to do with them, Have you gotten to kill any pigs with one? wondering how they did.

No, I never shot a pig with the 140 Hawk, but I have shot some with the 130 BST and the 150 SGK. The 150 SGK really smacks 'em upside the head :a21:. That load sounds like a twig snapping, then you hear the pfffffff of the bullet flying. That "THWAP" sound, made by the bullet hitting the pig's head, is much louder than the click of it going off.:a04:

01-11-2011, 07:06 PM
Thank you for the info! I'll try to not blow myself up.

01-11-2011, 07:07 PM
Question?, what about resizing 7pm bullets down to .277, then you have heavy bullet that mabey you can crimp properly?

01-11-2011, 08:03 PM
Question?, what about resizing 7pm bullets down to .277, then you have heavy bullet that mabey you can crimp properly?

I wouldn't bother. We have way too many good bullets as it is now. Anything over 160 grain, even with 1:10 twist, is not likely to be stable. I am not crimping these loads, either.