P.K.
03-01-2013, 06:19 AM
Range Report: Trail Boss Subsonic Loads
When I came across an article on working up Trail Boss in "modern" cartridges for subsonic loads I was interested to say the least. The author also was kind enough to use three fairly common chamberings, two of which are widely used and one that is making it's name known. Those being, .223/5.56, 6.8SPC and .308 Win. I am lucky enough to own two of the three so I decided to give these loads a try.
First impressions upon opening up IMR's offering to the Cowboy Action crowd is the size of the individual grains. Visually they look like super sized donuts for dust mites. My second thought was that it won't take much to do the trick. Trail Boss is a high volume, fairly quick burning powder that falls on the Burn Rate chart at #19(Hornady's 8th edition) next to ZIP( #18) and between Win-231 and HP-38.
My entire drive for this endeavor was for a quiet performing round for my platforms, both auto-loaders, with out the need of a suppressor. Neither as tested will generate the pressures needed to operate a Direct Impingement gas system. However, the 6.8 SPC offering does use a Gas Piston with an adjustable gas usage port system. I didn't try to adjust the output from the factory setting of #2, but will in the future after tweaking the load and securing the use of a chronograph to substantiate my observations from the range.
Loading cases with Trail Boss was about one of the easiest tasks involved with this experiment. Though it meters very well in my Lyman #55 I opted for a Lee Dipper and my powder trickler with a Hornady digital scale. While the flakes are very large it measured well and flowed through the trickler with out any issues. While filling cases, my funnel was the bottleneck in the process, a tap or two will clear any blockages. After filling, a quick visual of each case showed what I suspected earlier, a little indeed goes a long way. Roughly 1/2-2/3rds of my useful case capacity was filled in my two chamberings with their individual payloads.
The projectiles used were straight J-words, though I am working up Boolits for both, neither was ready at this time. In the .223/5.56 category, Mid-South's "Unnamed Premium Bullet Maker's" Varmint Nightmare and Hornady's #2266 were used. Both are 55gr. SP's with Hornady's having a cannalure. For the 6.8 SPC both offerings were from Hornady, the #2720 and #27200 both are HP's with the latter having a Boat Tail and cannalure.
While finishing the article and working up my loads with the recommendations provided I had hoped to mirror the author's results. I figured if a Dad taught garage reloader can get close to these numbers anyone can. The flaw in my logic is he probably used much of the same equipment I did and had a wider range of projectiles to choose from. While our bullet makers differed the grain weights on two of his test loads were the same. So with that in common I came up with these loads:
.223/5.56
Rifle: CMMG upper, 1:7 twist, 16 inch bbl.
Case: Federal
Primer: CCI #41
4.0 grains of Trail Boss
COL: 2.200
6.8 SPC
Rifle: Ruger SR556/6.8, 1:10 twist, 16 inch bbl.
Case: Hornady
Primer: CCI#41
7.9 grains of Trail Boss
COL: 2.245
On the range both performed beyond my expectations, accurate, quiet and FUN! When fired the .223/5.56 sounded little more than a .22LR with out the sonic boom/crack. The 6.8 was about on par and maybe a little more depth to the report but not much. Neither came close to cycling the action's in either so a plus for quiet operation, with a suppressor these will be darn near silent.
At the end of the day I was impressed with the accuracy of both but more so with the 6.8 SPC. With it's heavier projectile it would make an excellent "whisper" round. My testing was at 50 yards, the same as the author's mentioned earlier. My results differed in that I had exceeded his results. However without a chronograph to substantiate velocities it's pure conjecture on my part. All I have are his published results of a 1.11" group out of a comparable barrel and twist as mine. My group's measured .70 with the plain base HP and .368 with one flier( thanks to a 110BA .338 next to me on the range), for the BTHP.
The comparison of the .223/5.56 loads were close but because of mine, being a Clone-4 and the authors' Weatherby Vanguard 1:12 with a 22in bbl the deviations in the loads were not up for comparison. His failed to stabilize in all loadings save one, the 55gr. bullet. That was another reason for trying these loads, if the longer bbl wasn't working how about a shorter one with a faster twist? While mine will never be a one holer, 1 inch groups are just fine for me. It is what it is, a volume gun.;-)
62766
***To read the "author's" article I mentioned and data published pick up a copy of Hodgdon's 2013 Annual Manual.***
When I came across an article on working up Trail Boss in "modern" cartridges for subsonic loads I was interested to say the least. The author also was kind enough to use three fairly common chamberings, two of which are widely used and one that is making it's name known. Those being, .223/5.56, 6.8SPC and .308 Win. I am lucky enough to own two of the three so I decided to give these loads a try.
First impressions upon opening up IMR's offering to the Cowboy Action crowd is the size of the individual grains. Visually they look like super sized donuts for dust mites. My second thought was that it won't take much to do the trick. Trail Boss is a high volume, fairly quick burning powder that falls on the Burn Rate chart at #19(Hornady's 8th edition) next to ZIP( #18) and between Win-231 and HP-38.
My entire drive for this endeavor was for a quiet performing round for my platforms, both auto-loaders, with out the need of a suppressor. Neither as tested will generate the pressures needed to operate a Direct Impingement gas system. However, the 6.8 SPC offering does use a Gas Piston with an adjustable gas usage port system. I didn't try to adjust the output from the factory setting of #2, but will in the future after tweaking the load and securing the use of a chronograph to substantiate my observations from the range.
Loading cases with Trail Boss was about one of the easiest tasks involved with this experiment. Though it meters very well in my Lyman #55 I opted for a Lee Dipper and my powder trickler with a Hornady digital scale. While the flakes are very large it measured well and flowed through the trickler with out any issues. While filling cases, my funnel was the bottleneck in the process, a tap or two will clear any blockages. After filling, a quick visual of each case showed what I suspected earlier, a little indeed goes a long way. Roughly 1/2-2/3rds of my useful case capacity was filled in my two chamberings with their individual payloads.
The projectiles used were straight J-words, though I am working up Boolits for both, neither was ready at this time. In the .223/5.56 category, Mid-South's "Unnamed Premium Bullet Maker's" Varmint Nightmare and Hornady's #2266 were used. Both are 55gr. SP's with Hornady's having a cannalure. For the 6.8 SPC both offerings were from Hornady, the #2720 and #27200 both are HP's with the latter having a Boat Tail and cannalure.
While finishing the article and working up my loads with the recommendations provided I had hoped to mirror the author's results. I figured if a Dad taught garage reloader can get close to these numbers anyone can. The flaw in my logic is he probably used much of the same equipment I did and had a wider range of projectiles to choose from. While our bullet makers differed the grain weights on two of his test loads were the same. So with that in common I came up with these loads:
.223/5.56
Rifle: CMMG upper, 1:7 twist, 16 inch bbl.
Case: Federal
Primer: CCI #41
4.0 grains of Trail Boss
COL: 2.200
6.8 SPC
Rifle: Ruger SR556/6.8, 1:10 twist, 16 inch bbl.
Case: Hornady
Primer: CCI#41
7.9 grains of Trail Boss
COL: 2.245
On the range both performed beyond my expectations, accurate, quiet and FUN! When fired the .223/5.56 sounded little more than a .22LR with out the sonic boom/crack. The 6.8 was about on par and maybe a little more depth to the report but not much. Neither came close to cycling the action's in either so a plus for quiet operation, with a suppressor these will be darn near silent.
At the end of the day I was impressed with the accuracy of both but more so with the 6.8 SPC. With it's heavier projectile it would make an excellent "whisper" round. My testing was at 50 yards, the same as the author's mentioned earlier. My results differed in that I had exceeded his results. However without a chronograph to substantiate velocities it's pure conjecture on my part. All I have are his published results of a 1.11" group out of a comparable barrel and twist as mine. My group's measured .70 with the plain base HP and .368 with one flier( thanks to a 110BA .338 next to me on the range), for the BTHP.
The comparison of the .223/5.56 loads were close but because of mine, being a Clone-4 and the authors' Weatherby Vanguard 1:12 with a 22in bbl the deviations in the loads were not up for comparison. His failed to stabilize in all loadings save one, the 55gr. bullet. That was another reason for trying these loads, if the longer bbl wasn't working how about a shorter one with a faster twist? While mine will never be a one holer, 1 inch groups are just fine for me. It is what it is, a volume gun.;-)
62766
***To read the "author's" article I mentioned and data published pick up a copy of Hodgdon's 2013 Annual Manual.***