I'm looking to load a 404 Jeffery with Trailboss reduced loads. The loads I find are for the standard 400 grain bullets. However I have a bunch of 44/40 bullets that with a run through the sizing die fit well in the 404. these bullets weigh 200 grains- half of what the loading data is based. What effect on ignition of TrailBoss is there from using a lighter bullet?

Have been shooting 200 grains out of a 45 colt with no problems,just follow the instructions.

the instructions say determine powder capacity volume, x.7, that is your starting load. the articles that I have read used this method but in all cases used 400 grain bullets. So, does reducing bullet weight by 1/2 affect the burn rate/performance of TrailBoss?

Might do well to call the powder company. That's what I did in loading with trail boss for a 470 double.

Trail Boss is loaded by volume, not weight. I use it in my 416s and 458s all the time , can't see how you would have a problem. Its way under pressure anyway as long as you don't compress it.

I got an e-mail back from Hodgdon customer service. Load data is done by weight, but the amount is determined by filling the case to the bullet base with TrailBoss, then weighing it. this is the maximum load. 7/10 of this weight is the starting load. No reference was made regarding the weight of the bullet being pushed out of the barrel, so the inference is that it doesn't matter (within reason). I measured the 404 Jeffery and to the base of a 400 gr bullet the charge is 30 gr. to the base of a 200 gr bullet it took 32 gr. so the starting load will be 21 & 22 grains. So off to the loading bench.