I might just try and trim everything to the shortest piece of brass because I know none of them are even close to being at max length and they don't grow much. I push the shoulders back about .002. So maybe I will just work my charge back up using the same seating depth. Sometimes I wonder how accurate my chronograph is too. I know it's a great tool but i think it gets me in the ball park for velocity but don't know how accurate it is from shot to shot. Now what about the cases being clean? I use a vibrating tubular with corn cob media. So it really doesn't clean the inside of the case very well. Is there possibly there is getting carbon built up inside the case and affecting pressure and case capacity?
Powder chargers and accuracy?
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Mikecr
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Never trim brass to 'shortest piece'. That's the same as trimming them all to a wrong/anomalous value.
The carbon in your cases is your friend. It hurts nothing and it's consistent lubing inside necks for bullet seating.
You can look up Berger's full seating testing, and do this during fire forming of new cases. When these cases are fully stable in dimensions, and with best coarse seating identified with testing, then begin powder load development.
The carbon in your cases is your friend. It hurts nothing and it's consistent lubing inside necks for bullet seating.
You can look up Berger's full seating testing, and do this during fire forming of new cases. When these cases are fully stable in dimensions, and with best coarse seating identified with testing, then begin powder load development.
Capt RB
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I have loads for virgin brass and fireformed brass. They are not the same in speed or seating depth for the best overall however I know that and have different profiles and dope cards for them.
I also use a drop tube if I'm at case filled charges even when I do the first testing. Also if your charge is not 100% changes in shooting angle can have dramatic changes in results. I see this with faster powders mostly with poor case fills.
Things to check seating pressure, Take virgin, once fired and whatever number fired brass your using. Make a load up did they feel the same? You can use a digital fishing scale on your press arm to measure and don't be surprised. Brushing the necks can help with es Annealing can also clean that up however your going to see a bit of velocity loss most of the time.
Have you checked your velocity since you started to notice this change?
Cool thing about all of this is you get to drag all your crap ur stuff to the range and shoot some more
I also use a drop tube if I'm at case filled charges even when I do the first testing. Also if your charge is not 100% changes in shooting angle can have dramatic changes in results. I see this with faster powders mostly with poor case fills.
Things to check seating pressure, Take virgin, once fired and whatever number fired brass your using. Make a load up did they feel the same? You can use a digital fishing scale on your press arm to measure and don't be surprised. Brushing the necks can help with es Annealing can also clean that up however your going to see a bit of velocity loss most of the time.
Have you checked your velocity since you started to notice this change?
Cool thing about all of this is you get to drag all your crap ur stuff to the range and shoot some more
Kansaswoodguy
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I would not trim to shortest case length either just book length. Clean cases are pretty to look at but do nothing for accuracy. If I don't trim my cases and there is differences in case lengths my groups open up to around 1.25-1.5MOA after trimming my groups drop to around 3/4MOA. I use the cheap Lee case trimmer that can be chucked up into a drill and spins the case this is makes it very quick to trim and chamfer the cases and they can be cleaned with 0000 steal wool held against the cases when spun. I tumble my 223 brass but I shoot hundereds of rounds of it. I never tumble my 6.5 Creedmoor brass just resize/deprime it pushing shoulder back .003 run it in the Lee trimmer, chamfer then use the steel wool on the cases to clean them up a bit and use the wool on the case mouths to give them a quick polishing.
Kansaswoodguy
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Mikecr
Well-Known Member
A book value doesn't matter. This is YOUR chamber, you should measure chamber end and set your clearance(with trimming) when the brass encroaches that desired clearance.
If your cases are not lengthening with each reload cycle, congratulations on a sound reloading plan. Determine the median length and trim to that, preferably at around 5thou clearance.
If your cases are lengthening a lot, likely due to FL sizing, let them get within 10thou of chamber end and manage that easy clearance.
Any more clearance than that leads to heavy carbon buildup in the chamber neck. This becomes a new chamber end, and then you potentially have zero clearance from it.
If your cases are not lengthening with each reload cycle, congratulations on a sound reloading plan. Determine the median length and trim to that, preferably at around 5thou clearance.
If your cases are lengthening a lot, likely due to FL sizing, let them get within 10thou of chamber end and manage that easy clearance.
Any more clearance than that leads to heavy carbon buildup in the chamber neck. This becomes a new chamber end, and then you potentially have zero clearance from it.
The Oregonian
Well-Known Member
Maybe this is a dumb question, but how do you measure max case length for a chamber?
Mikecr
Well-Known Member
Sinclair sells a chamber end gauge.
You over-trim a case, seat the pin in the neck, chamber, extract, measure case + pin OAL.
You over-trim a case, seat the pin in the neck, chamber, extract, measure case + pin OAL.
The Oregonian
Well-Known Member
Thanks...just ordered some.
MagnumManiac
Well-Known Member
You can make your own as I do.
Using a pipe cutter on a sized and trimmed piece, cut the neck about halfway from the mouth, then seat a short/light bullet for calibre, place the ring of neck you cut off over the bullet and chamber it. The gap left is the distance to the chamber end.
I have used several techniques, this one stays together permanently and can be stored for each barrel and referenced whenever needed.
I normally allow .005" too, but a few of my chambers barely grow, in those cases I just trim until square with a light skim.
Cheers.
Using a pipe cutter on a sized and trimmed piece, cut the neck about halfway from the mouth, then seat a short/light bullet for calibre, place the ring of neck you cut off over the bullet and chamber it. The gap left is the distance to the chamber end.
I have used several techniques, this one stays together permanently and can be stored for each barrel and referenced whenever needed.
I normally allow .005" too, but a few of my chambers barely grow, in those cases I just trim until square with a light skim.
Cheers.
