Home Forums Hunting & Shooting Express Rifles and Big Bores Only Trail Boss powder in 505 Gibbs

I have been wanting a reduced load for my 505 Gibbs to give me more trigger time other than full throttle loads that I have now.I read somewhere that Trail Boss could be used to greatly reduce calibers like the 460 weatherby but I only saw this once in all my searching. I already use this powder in my 300 BLK and 308 subsonic loads but am leery of using it in such a large case with heavy bullet by just reading only one recommendation. As I understand it you fill the case with the Trail Boss til it touches the base of the bullet and that's the maximum load then multiply that weight times 70% and that's your starting load. My question is has anyone on this forum experimented with this powder. I know when I first started loading for the 505 I found out that with certain powders that the case needs to be full or close to full to operate safely. I was getting hangfires and incomplete powder burning with H4831SC that left minor space between base of bullet to powder. I've been reloading for over 40 years and have never experienced a caliber this sensitive to powder volume.

I've used Trail Boss in my 416 Rigby using the formula you posted. I used 400 Gr. bullets. Never used more than the starting load. Worked fine for me.

I loaded 5744, Blackhorn 209 and WC860 in my Gibbs. All with a 600 grain cast bullet. Wc860 is a fantastic powder since you can fill the case. Federal 215s are the only primer I used. 5744 from accurate made very nice reduced load that will go through a plow disc at a hundred yards.

The Dec./Jan. 2022 issue of HANDLOADER (335) has TB data, one load anyway. Borrowed it from loaddata.com. You might want to peruse their charts and see if there’s something that makes subscribing profitable to you. Gotta pay to get the charge levels.

470 Hayley cast Hodgdon Trail Boss 35.0 1405

Since Mr. Hayley has passed, it’s doubtful that bullet is available, but it gives you an idea of the possibilities. TB is pretty forgiving stuff within its parameters. I'd pick a bullet and follow the Hodgdon guidelines.

I forgot to post that I want to use my jacketed bullets with this powder. I used to cast bullets in the past for all my calibers but quit casting 15 years ago. I know they talk about powders for lead bullets but don't see why jacked bullets wouldn't work. I am posting a picture of my first experience loading this 505. The load of H4831SC was loaded within the suggested data with only about 3/8" gap between the base of the bullet and the powder level. I got about 5 hang fires out of the first 10 rounds so I quit until I got woodleigh's loading manual book that stated that you need to load 505 Gibbs fully wih no or little gaps between the between powder and bullets. The picture that I added shows what the necks on 4 cases looked like. 4 good sized dents. In all my years reloading I've never experienced this. I only mention this in case anyone else experienced this same oddity.

I've used Trailboss in my 500NE no problemo.

The main problem using long jacketed bullets is that if the velocity is too low the bullet may get stuck in your barrel. I know few guys that had this happen to them when developing 220gr loads in a 30/06. Cast bullets offer less resistance and are a safer option. Even though you no longer cast you should be able to source some commercially made cast pills for your 505.

I’ve used Trailboss to make up subsonic cast bullet loads for a 50/90 and it worked perfectly. The recoil was very mild and being subsonic, the load was very quiet.

FWIW the supplier below lists a cast bullet that would be suitable. More than likely he could also size down one of several 0.510-0.512 bullets.

https://bullshop.weebly.com/-50-caliber-cast-bullets.html

I thought about the cast bullets on the internet but the only ones that were hard enough for this situation were all .511 sized. I even thought about buying some of these and sizing and lubricating them myself as I still have my lubricator sizer from when I did casting. I'd have to buy the right sizing die if I did. I was hoping that I could avoid lead bullets as I stopped shooting my cast bullets years ago because it was a pain in the neck cleaning my gun every time I went from lead to jackets. They never grouped well. I loaded up about 5 this morning using Hornady DGS 525gr bullets. Tomorrow is supposed to be 70 degrees here so I'm going out the range to try them out. I loaded them 38grs-44grs. I figure maximum load was 52.5 grs and minimum load was 36.5 grs of Trail boss so I'll know more tomorrow. I'm taking my Chronograph with me. Thanks to everyone for their input so far.

I sold several thousand of my 600 grain gas checked bullets to a gentleman. He shot them out of a Joe Smithson bolt rifle.
His son got his own Gibbs and killed some Cape Buffalo with my cast bullets. I have shot lots of cast bullets from my Gibbs and never had a leading problem. The gentleman that bought my bullets never mentioned any leading or cleaning issues. My bullets were sized to .507 and were not “hard cast”, whatever that means. The bullets that killed Cape buffalo were water quenched tire weights, all of them exited. They got their own mold. I have killed bison bulls with my Gibbs, always exited two thousand pound animals. Shot some bison heifers. There was an immediate change in either’s attitude when smacked by a 600 bullet.

Should be interesting.

My trip to the range the other day was successful other than I didn't change the battery in my chronograph before I left and found that it was dead after setting it up to shoot. For the first time since buying my .505 years ago that I can say it was an enjoyable experience. My previous loads were 98grs and 104grs of reloader15 using a 1" long foam cord filler. The recoil was stout but not as bad as my original loading of H4831sc loads. My tolerance of recoil from shooting from a bench diminished in my old age. The 104gr loads registered 2,100 when I last tested them. We have had a real mild winter so far but I may have to wait another month to go out to test the one's that I loaded yesterday. I changed the battery in my chrono as soon as I got home. This bunch was loaded from 41grs-50grs of Trail Boss.

Trail Boss over a 385gr. Cast bullet pushes 2000 fps in my .470 Merkel. This brings the sights to bear at close to zero at 50yds. I forget the exact charge, but it produces low pressures.

I don't have experience with the 505 Gibbs, but have shot quite a few practice loads with my 450 Rigby (416 Rigby case/0.458 " bullet) and the 500 NE 3". Both are large capacity cases so that may help you with the 505 Gibbs.

In the 450 Rigby I used both Trail Boss and reduced H-4895 loads with a Berry's 350 grain plated bullet reaching velocities of about 1670-1740. There are directions on the Hogdon site for the calculation of the reduced loads in large cases. Quite pleasant to shoot as practice and a few full power loads in each session.

In the 500 NE I used mostly reduced H-4895 with FPGC 545 grain lead bullets (commercially available) but didn't run them over the chrono. I used a Lyman 450 sizer with a 0.509" die to size these down. Worked well as did the Trail Boss loads with the same bullets.

I used the start and max load guidance you described ans loaded a bit more more on the top end.

This is an interesting thread - I never knew anything like this was possible! I am going to have to give this a try in my 1895 Marlin CB 45-70 GOVT.

I have found best accuracy with Trail Boss loads to be at about 85% of the formula.
Also, if you decide to try cast bullets Bullshop as mentiond above makes excellent bullets and they are to order as far as hardness. Not long ago I had him cast some +/- 10bhn bullets for my 348 Winchester.
Good luck to you!
Rick

I've loaded 450 gr cast bullets in my 500 Jeffery to 1050 fps using Unique. My data is back at home at would take some digging to find. Works great, like a giant 22 lr. I would not use jacketed bullets for the reduced loads, too expensive and the risk of getting stuck. I also wouldn't use trailboss for anything other than handgun level loads. The challenge with the 505 and cast is fall between the .500" cast bullets for the 500 S&W and the .510" for the 500 Linebaugh. You could paper patch the .500" cast bullets up to .505" and there are plenty of companies that cast those pistol bullets.

As a follow up to my original post I've finally got some good results after replacing my chronograph. I loaded my .505 with various loads ranging from 43 grs to 50 grs with trailBoss and found that the most consistent load turned out in the 45gr and 47gr. Targets were consistent in groups with these loads as can be seen in my picture. These are 5 shot groups and were shot at 50 yards from a rest and 4X scope. These loads pretty much filled the cases within about a 1/4" from making contact with the base of the bullet. Recoil was still there but noticeably lower than full throttle loads that I shot 40 rds in my last session and it never bothered me in any way. They chronographed around 1500 FPS. Not close to the 2100-2200FPS of regular loads but I can get a lot more shooting time in with this rifle now. Empty brass comes out the cleanest that I've ever experienced from fired brass. I don't need to tumble them now.