Would anyone care to comment on what their opinion is for a max Trail Boss load, using a 158 grain LSWC bullet. How many grains of powder would constitute a max load.? I have determined that a max load is somewhere in the neighborhood of 5 to 5.1 grains.
Any and all comments would be appreciated.

First, the Hodgdon data:
Hodgdon
Powder Trail Boss
Bullet Diameter .357"
C.O.L. 1.610"
Starting Load
Grains 3.2
Velocity (ft/s) 754
Pressure 16,500 CUP
Maximum Load
Grains 4.2
Velocity (ft/s) 865
Pressure 20,400 CUP


Second, a "loader mentor comment":
From your comments, I infer you have noticed the max pressure on the Hodgdon data is 20,400CUP, and you want to extrapolate data MORE than is listed and GUESS what the pressure will be. Seems reasonable, right?
My advice is NOT to EXTRAPOLATE nor GUESS on loading data, due to non-linearity of pressure curves.
Personally, if I wanted to go faster I would pick another powder from the loading tables that has a tested load for the speed I want.

__________________
Science plus Art

I use 4 grains of Trail Boss for 158 grain cast Bullet the max is 4.2 grs. I would not go above published data .
I have good results with this load.

Whoa, be careful there....

There are old reloaders,
There are bold reloaders
But there are no old, bold reloaders.

__________________
Dave

Besides OKFC05's comments you need to read Hodgdons remarks about Trail Boss. TB must not be compressed! When loads exceed approximately 90% of available space in the case this powder becomes quite erratic, with sometimes extremely high pressures. While loading for my Italian Vetterli-Vitalli a few years ago I got one batch that was basically a full case, not quite, but close! If you are not familiar this is a black powder military rifle in nominally 11mm. Pressure was high enough with one round that the cartridge case was destroyed and had to be driven from the chamber! No idea what the pressure was, but if it had been only slightly higher the case would have failed, the rifle probably destroyed, and I would likely have been severely injured!***

You can push the published data with many powders with no serious consequences, if any, but Trail Boss ISN'T ONE OF THEM!!!!!! Don't do it. Almost any other powder (Literally any!) will give better performance than Trail Boss. If you don't want full magnum performance use Unique, Universal, Power Pistol, BE-86 etc. It will be cheaper than Trail Boss too!

*** Note: I have been loading for nearly 60 years, have never blown up a gun or damaged one, and have often pushed the limits of published data very far. Forget Trail Boss except for using published data, or in loads that do not exceed 70% of available case volume, just as Hodgdon recommends. The story above is my own experience, not "Something I saw on the Internet"! Heed manufacturers warnings with this one.

__________________
Gunsmithing since 1961

Well OKFCO5 and ALKA gave you the real info, but I just have to ask, how did you arrive at:

"I have determined that a max load is somewhere in the neighborhood of 5 to 5.1 grains."

Where did that come from??

Hodgdon data gives you the MAX

Set your sights on pistol reloading data | Hodgdon Reloading

__________________
Still Running Against the Wind

Good evening
It is my understanding that trail boss was engineered for light loads. To me that means a very fast powder do not hot rod it. If you want a firebreathing .357 load get a pound of H110.
Regards
Islander

Actually IMR lists 70% of available case volume as a starting load and 100% as a max load.

http://www.imrpowder.com/PDF/Trail-Boss-data.pdf

I wouldn't be too sure of that. Elmer Keith was loading the 38 Special to near magnum levels back in the mid 20's and in the 30's he was doing something quite similar with the 44 Special. However one thing worth taking note of that he admitted to blowing up a few revolvers with his experimenting. I also expect that he was taking copious notes and was also very careful when testing a new, more powerful loading. Most likely he used the old gun in a fixed rest with a long string on the trigger when doing this because IIRC he had all 10 fingers when he passed away in 1984.

Point is that if you are willing to blow up some perfectly good firearms and willing spend the money for bullet and fragment resistant screens you could become an Old Bold Reloader.

However if you are like most of us and really don't want to throw money down the toilet then the most sensible action is to take the advice of all those suggesting that you work within the limits set forth in the rather wide variety of load manuals we have today.

I'll also point out that Trail Boss is not the least bit suitable for a 357 Magnum, the burn rate is just too fast. I would suggest that you try using either Accurate #5 or Accurate #7 for your Magnum loads. You won't get true Magnum velocities with these powders but you will get close and my experiments using 158 grain Hard Cast Berry's bullets resulted in the # 7 loads producing only a tiny hint of leading and the # 5 loads didn't produce any leading at all.

It can't be overloaded unless you crunch up the pellets which is a big no-no.

__________________
"He was kinda funny lookin'"

That was then, Hodgdon is now! Hodgdon is now the distributor for IMR and Winchester branded powders. To the best of my knowledge IMR is no longer publishing an annual reloading manual, and has not for several years! Data for the Winchester, and IMR, powders is now listed in the Hodgdon "Annual Manual".

Trail Boss is manufactured in Australia and imported by Hodgdon, which has distribution rights. Trying to be cute, and critical over a petty detail, you are several years behind current industry information.

__________________
Gunsmithing since 1961

Maximum powder in the 357 case depends on the style of lead
158gr bullet from wc, swc or even a LRN that can have the
longest OAL due to some LRN do not have a cannelure and can be seated out farther to around 1.66".

A 158gr Lswc design seated with a OAL of 1.58" will have less
room available in the case, volume wise.

Trail Boss was not made for maximum fps...........
but rather light target loads, that are pleasant to shoot.
A 158 Lwc in a 357 case in my 6" with a full load hits 788fps.

A light load of Bullseye hits 918fps.
A good hand loader selects the correct powder for the job at hand, that will be safe for all.

Trail Boss was originally designed to fill the large cases that were originally designed for Black Powder. It's a fluffy bulky powder and it does fill those cases but it's not magic and has its limits.

According to Hodgdon:
Unless you are looking for a very light load in .357 Magnum brass it is not the correct powder for the job.

__________________
Freedom is never free!!
SWCA #3437

It's not my intention to dispute anyone, or to add fuel to the fire. This thread just caught my attention because I regularly use Trail Boss powder.

Just for kicks, I measured a 158 grain bullet up against the edge of a Bic pen and marked where the crimp groove is with a Sharpie on the pen barrel. Then I loaded a .357 case with Trail Boss and inserted the pen until the mark was hidden just under the case mouth, and weighed the powder. It came up to 5.0 grains.

While the IMR publication states that this is the max load, and would not be over-pressured, I think that the 90% rule that people are quoting is just common sense, and I use it myself. If I accidentally seat just a hair too much using the 100% load, or one of my cases is just a little shorter than the rest, I run the very real risk of compressing the powder; which is not good for Trail Boss.

So I multiplied the 5.0 grains by .70 and .90 to get a minimum load of 3.6 gr and a maximum of 4.6 gr. This is the most I would feel safe using with this round. Personally, I would stick with the published 3.2-4.2 gr using Trail Boss (which was designed for light lead loads); and like others have stated, if you want just a little more speed, use another powder.

Just my 2-cents worth.

Thank you Mr Flintstone , I thought sooner or later someone would add a little more info . I don't use trail boss so I couldn't add much .

If your intentions are:

1. Use a .357 magnum case so you don't get the crud ring by using 38 special cases in your .357 gun.
2. Want essentially a "cowboy action" light recoil load with your gun
3. Only have Trail Boss powder available

Then yes, it will work. You will be shooting a very low recoil load with a slow moving bullet that will be fine for target shooting or ringing steel plates.

My Lee 358-158-RF bullets seat to 0.4" depth. With that seating depth, 70% fill = 3.4g Trail boss which will give you 600fps out of a 4" barrel. 100% fill (bullet base barely touching the powder) = 4.8g will give you 770 fps. With a bullet seated shallower, you can fit more powder to get a little more speed. For instance, with a 0.3" seat depth, you should get 630 and 800 fps respectively with 70% and 100% fill.

Don't expect more out of this powder. It is meant to build up pressure fast to give a complete and clean burn at low charges and to keep bullet speeds and recoil down. You can accomplish the same with many other powders such as Red Dot, Titewad (and to a lesser extent Titegroup), Clays, e3 all at a lower cost per shot than Trail Boss.

The plus side of Trail Boss is that you fill nearly the entire case with the powder and you won't risk a double charge (or conceivably a triple charge with powders like Titegroup or Bullseye).

Use the right powder for the right job. If you are looking for a low recoil load that fills up the case to prevent accidental double charges, then Trail Boss is the right powder.

I think the deal with TB is those doughnuts are the key to its burn rate. Break the doughnuts and the nitrocellulose becomes free to combust whenever the temperature is right/flame reaches it, and you don't know when that will be or how many doughnuts are broken. That is the sourse of erratic results with TB.
I love the stuff. Using the 90% rule 4.6 grns is a really really fun cowboy load under a 158 LRNFP (aka beveled wadcutter). Fast, uh, no. Fun yes.

__________________
Certified Curmudgeon

As mentioned above, the TB pdf was published before Hodgdon had much data on it. The pdf was primarily for mouse fart loads in rifles.

If folks take the time to check the burn rate, TB is actually a pretty fast burning powder. If it was not for the 'Bulk" of it folks would have blown up a lot of guns by now!

9 oz of powder for the price of 16! What a deal. Smells funny also.

__________________
Still Running Against the Wind

Definite ammonia aroma, use outdoors. If you are paying pound prices, go somewhere else. I have found it in three states for price per ounce competitive with other propellants. (Admittedly the upper end, non VV ones).

__________________
Certified Curmudgeon

Hodgdon purchased IMR in 2003. For whatever reason Hodgdon continues to use the IMR brand name on certain powders, including the new Enduron line.

The annual Hodgdon manual from 2010 has an article written by Layne Simpson about Trail Boss. He writes about spending time in July 2003 with J.B. Hodgdon at Thales Australia Ordnance Land Systems, the manufacturer of Trail Boss and several other powders Hodgdon distributes. He writes about going to their range and shooting a new powder on which final development had just been finished. That powder would become Trail Boss. Obviously any official data printed about Trail Boss comes through Hodgdon, regardless of whatever brand they choose to print the data under. I know, just so 2003, right?

Interestingly, Simpson relates a conversation he had with Ron Rieber, who had been Hodgdon's head ballistician for many years. He quotes Mr. Rieber as stating that it is impossible to get enough Trail Boss in a case to exceed maximum chamber pressure. Rieber was also quoted in the June 2016 issue of Handloader as saying Trail Boss becomes erratic, not dangerous, if compressed. I believe that Mr. Rieber has probably forgotten more about ballistics than I'll ever know, so I choose to believe him.

Also interestingly, my .357 brass with a 158gr. Speer swaged SWC will hold 4.2 grains of Trail Boss to the bass of the bullet when the bullet is seated to the crimp groove. 70% of that is 3.0 grains. It would appear that Hodgdon printed their data with prevention of compression of the powder in mind and chose to back off just a bit because of the differences in molds and alloys involved in casting. The Speer bullet is pure lead and will be shorter than most cast 158gr SWC bullets.

I have no idea where the O.P. got his data from. He should repeat and reweigh the charges he got if he actually followed the the "fill to the base and call that 100%" rule. If he didn't get his charges by actually weighing powder, he should do so if he wishes to use Trail Boss, or simply use Hodgdon's data.

Thank you everyone. What I did, is measure the 158 gr swc bullet and subtracted the length from a new .357 case. I then machined the case down to this measurement. I filled the shortened case to the max with Trail Boss and measured the charge.
I just finished shooting a 4.5 grain load of Trail Boss in .357. Recoil was mild, brass ejected without any sticking, there was no visible evidence of flattening on the primers- The weapon is used was an old Ruger security six, with a 6 inch barrel. There was no barrel leading or lead build up in the forcing cone.

Thank you again for all your comments.

I do not buy it. Tried one pound of it. Have no use for it.

Too many other powders to keep track of.

__________________
Still Running Against the Wind

You will not notice any changes in primers until it's too late!

So you started with a higher than load data amount?

Better to start low and work up, not the other way around!

You lucked out. Other powders may not be as forgiving.

Good luck,

__________________
Still Running Against the Wind

It sounds like you forgot to take into consideration the case head and web thickness when you subtracted the length of your SWC bullet from a new .357 case. That would explain your finding a max of 5.1 grains.

I agree with Rule3 about your choice of a starting load. You won't always be lucky. FWIW, visual examination of primers and cases tell you nothing about cartridge pressure except that it was not high enough to blow up your gun.

Get some Universal or Unique and use 6.0 grs of either under the 158 gr lead bullet in 357 Mag cases. Accurate loads.

Trail Boss for Cowboy action in 45 LC...

Slow is sometimes good..................

So, Nevada Ed,

What was the load of Trail Boss?

Very seldom do I give out loading data........manuals are for that.

However with the same bullet I can get a tighter group with Red Dot at 755 fps with the 686......
so no need to worry if you can't find Trail Boss or think it cost too much.

Nevada Ed,
If you get better than that group (.75"), that's some great shooting.
I have over 20 powders I have tried with a dozen different bullets and Trail Boss gave me my single best groups at 25 yards of all my calibers and combos.
Shooting a Colt Diamondback 38spl with 3.5g of Trail Boss I got .50" groups
and thought that was a world record for me.

QUESTION?
Has anyone else noticed the Hodgdon Data Center lists Trail Boss 158g LSWC in 38 spl and 357mag with exactly the same max load (4.2g)?
That can't be right. Case volume is different.

I use Trail boss frequently and find that I get better consistency with magnum primers. I use the 90% fill thinking with plated bullets. My range won't allow lead. When my 5 pounder runs out I may well go back to AA2 or 231.

__________________
Foster Positivity.