Hey Dez;
The need to compress BP in the 70 and 55 is highly over-rated...especially a heavy compression. Some compression is important, but there is no need to exert excessive pressure to simply seat the bullet. If you need the wife to come help you seat bullets in the case in order to get good compression you are doing it wrong!!!! Forget about using a 10 ton hydraulic press for seating bullets as well!!!
Here is a bit of a hint...as partially referred to on a thread about shooting the trapdoor 45-70. Do a side by side comparison of a loaded round you are currently using with a bullet to see where the base ends up...measure this if you would like. Then charge an un-primed sized case with the load you use, measure the depth of the powder in the case then compare the two. If you see a 1/4" or more difference then you may have a bullet deformation issue. Experiment with overall length or reduced powder charge. Another option is to use a drop tube, which will compact the powder in the case though you should do the previous test over again and note the difference. I have experimented with 24" and 36" drop tubes and actually did see a difference, though not dramatic. Beside this, believing that bullet seating will consistently compress powder is fallacy. I have confirmed this by pulling a bullet on a loaded 45-70 to see how compressed the powder is. The first 5/-16" was compressed and partially crushed the balance was loose powder in the base of the case. Using the drop tube eliminated this.
However...if you are currently loading your rounds with no deformation and accuracy is acceptable, then don't worry about it!!! The system you are using is working and producing good consistent accuracy, no need to fook with it.
I used to hear guys babble on about how accurate their gun is with this bullet or that bullet and the $300 mold they had have specially made for their gun. Funny thing is, these guys never placed in any match I shot against them in. They always had one excuse or another, a gnat landed on the barrel just as the shot went of or they passed wind at the same time, the trigger got messed with, or the sights were changed, the range was not right...yada, yada, yada.
The key thing is to follow the K.I.S.S. principle...you know what it means. Tell those "self proclaimed" experts all the silly crap you did to make your gun shoot. Make up some wild stories about mining your own lead, mixing ffg with atomized martian dust, making bullet lube out of earwax and ground up yak hoofs and tell them how great it works. They will swallow it up like nuts...or they will think you are nuts.
Cheers