let's break this down.
- Thread starter fiver
- Start date
Okay. I'm asking strictly for BP so sorry--45-70. The veteran shooters I've heard from thumb seat for no neck tension to very light, but definitely no crimping. (I only use fire formed cases.) As for seating depth, barrel-dependent of course, some "jump" and some engrave. My testing said off the lands was best, but neither is there any free bore/throat. Our powder has a slower burn rate, but consistent b/c of compression. Also, my newest mould is a "money," w/ reduced first band which probably helps with the "running start" hypo. Some shooters pack powder in and greatly compress, others seem to be considering optimum charge weight plateaus and possibly the traveling sine wave harmonics. My experience was that this barrel/rifle liked the same charge of 68gr regardless of bullet, maybe suggesting the sine wave harmonics hypo or maybe implicating the formula for barrel volume per powder charge for complete burn, or both. The alloy is 20:1 so obturation is in full effect tho I might like the bullet dia to be .001" larger. Finally, studies have been done showing optimum compressions for different powders, but I don't know whether shooting for this will result any longer in the OCW plateau--whether the 68gr under nearly .40" compression will yield same ladder results as, say, 63 gr. (next guestimated OCW plateau down), but I'll be closer to the .25" optimum compression for this powder. Trouble is, this is my heaviest bullet, and deepest seating, so all the parameters might line up better with the lighter charge, BUT this is our 1K yard cartridge, and fear that the lighter charge will hamstring us. Moreover, have read that this mould/bullet profile requires upper limit (1300+ fps) MV for optimum BC. Don't have a chrony.
Maybe there's a question here. Might a slight neck tension help compensate for a loss in charge/pressure?
Do I HAVE TO stay @ 68gr and compress even further for long distance? Dunno whether a simple vertical adjustment will do if we're also sacrificing BC due to drop in MV with a lighter charge.
Testing these new bullets/loads Wednesday, but only have access to 200 yds. We have a 1k match coming up in 2 weeks--our 1st match ever. Other option is to go w/ a different powder that likes twice the compression. This is my wife's load--gonna go ahead and get her a separate recoil pad for her torso. Want her to be competitive. Thanks.
Maybe there's a question here. Might a slight neck tension help compensate for a loss in charge/pressure?
Do I HAVE TO stay @ 68gr and compress even further for long distance? Dunno whether a simple vertical adjustment will do if we're also sacrificing BC due to drop in MV with a lighter charge.
Testing these new bullets/loads Wednesday, but only have access to 200 yds. We have a 1k match coming up in 2 weeks--our 1st match ever. Other option is to go w/ a different powder that likes twice the compression. This is my wife's load--gonna go ahead and get her a separate recoil pad for her torso. Want her to be competitive. Thanks.
Last edited:
fiver
Well-Known Member
that's a lot to consider, and actually too much to try at one time it'd be swinging for the fences hoping to make contact for sure.
if it were me I'd keep what you have now, and work on the neck tension.
many of the B/P shooters I know that are super serious about it have a routine and usually it includes annealing the cases after every firing.
cleaning, and sizing.
they didn't say how they size nor how much, and in my ignorance [back then] I assumed full length or partial full length.
but have learned a little bit better since then.
after you find that routine of consistent neck tension I think you'll have a better handle on the next step.
more powder etc based on what you see down range or within the barrel.
one other thing I know many of them do/did is place a disc of paper in the base of the case before adding the powder to slightly help retard the primers affect.
if it were me I'd keep what you have now, and work on the neck tension.
many of the B/P shooters I know that are super serious about it have a routine and usually it includes annealing the cases after every firing.
cleaning, and sizing.
they didn't say how they size nor how much, and in my ignorance [back then] I assumed full length or partial full length.
but have learned a little bit better since then.
after you find that routine of consistent neck tension I think you'll have a better handle on the next step.
more powder etc based on what you see down range or within the barrel.
one other thing I know many of them do/did is place a disc of paper in the base of the case before adding the powder to slightly help retard the primers affect.
Thanks fiver, everything considered above was arrived at one step at a time, and I did begin, from the start, w/ coffee filter wad over the primer. I did a lotta research before getting the rifle and have continued, wh/ is why I came here. I was positing the above Q chiefly for my wife's sake--she's taken over this rifle and does well enough w/ the 520 grainer over 68 gr, so it's possibly much ado about nuthin on my part. However, I was also prompted by the need to taper crimp just to hold the bullets concentric, wh/ is not desirable. Turns out that the bore dia. on the 70 is larger than I'd had hammered into my thick head by all the pundits and owners of this rifle. Once I size to properly fit I will, of course, begin my testing all over again, but hey, that's why I got into this 100+ year old technology. That, and I'm part anal and part masochistic. Hopefully the other parts will fall in line.