I have a 280ai that was headspaced to be .004 shorter than the now standard saami standard. I can shoot Nosler 280ai brass out of it and it tight on the first firing and fire forms to the chamber well. However since it's .004 shorter than my saami standard redding die I can't get the shoulders to bump back. Can I take off a couple thousandths off the top of the shel holder to fix this?
Non standard 280ai won't bump shoulder
- Thread starter jsthntn247
- Start date
CatShooter
jsthntn247 said:
It is easy - take some #400 or #600 grit silicone carbide "Wet or dry" paper and put it on a flat surface... oil it with a light oil.
Measure the total height on the shell holder for reference, and then use figure "8" motions to lap down the top of the shell holder.
You CANNOT make too thin so it will break - it is just not possible (in one lifetime).
Gonna try it tonight and see how it goes.
CatShooter
No need to trim the brass any extra - Case length is case length... no matter where the shoulder is.
Hi 247,hi all
Just like Catshooter said,you can't go too far,you'll get sick of it all well before that...But you can start with 240 grit on a piece of glass oiled with WD40,and finish with 400 and 600 grit,I did it a while back to use a 280 FL die as body die for 270win brass that is shorter at the neck shoulder junction,it's a bit tedious but works fine in the end.Cheer up,you'll make it all right.Good luck to you.
Just like Catshooter said,you can't go too far,you'll get sick of it all well before that...But you can start with 240 grit on a piece of glass oiled with WD40,and finish with 400 and 600 grit,I did it a while back to use a 280 FL die as body die for 270win brass that is shorter at the neck shoulder junction,it's a bit tedious but works fine in the end.Cheer up,you'll make it all right.Good luck to you.
When sizing a case in a die with the die screwed down to the shell holder the reloader has the die adjusted to restore the case to minimum length, this method/technique is also referred to as being full length sizing. Some reloaders choose to grind the top of the shell holder and or bottom of the die, it works for them but it is not necessary.
I form cases for short chambers, I form cases that are shorter from the datum/shoulder to the head of the case .012" shorter than minimum length/full length sized.
All that is required is a feeler gage, place the feeler gage between the deck of the shell holder and case head when sizing.
As to your question, if you can manage the feeler gage you can determine the exact amount of material to be removed. I have an in-line, angle/butt cutter for making pilots, guides and head space gages, keeping the top of the shell holder square is not a problem.
F. Guffey
I form cases for short chambers, I form cases that are shorter from the datum/shoulder to the head of the case .012" shorter than minimum length/full length sized.
All that is required is a feeler gage, place the feeler gage between the deck of the shell holder and case head when sizing.
As to your question, if you can manage the feeler gage you can determine the exact amount of material to be removed. I have an in-line, angle/butt cutter for making pilots, guides and head space gages, keeping the top of the shell holder square is not a problem.
F. Guffey
CatShooter said:
Not quite true. I have a M1917 with .016" added between the shoulder of the chamber and bolt face. When trimming formed 280 Remington cases I add .014" to the length of the case.
SAAMI says" There are two three lengths, one is from the shoulder/datum to the case head, another is from the datum/shoulder to the case mouth and the other is from the case mouth to the case head.
F. Guffey
bigedp51
jsthntn247
Each brand of case, how many times it was fired and annealing will effect the spring back of the cases shoulder. Therefore there is no perfect shell holder height using a feeler gauge. You will need to take a smidgen more off the top of the shell holder to be able to compensate for all brands of brass and annealing.
You can always raise the die adjustment instead of lapping the die again a second or third time for harder brass with more spring back. Give yourself a little wiggle room for shoulder bump adjustment with your lapped shellholder.
Each brand of case, how many times it was fired and annealing will effect the spring back of the cases shoulder. Therefore there is no perfect shell holder height using a feeler gauge. You will need to take a smidgen more off the top of the shell holder to be able to compensate for all brands of brass and annealing.
You can always raise the die adjustment instead of lapping the die again a second or third time for harder brass with more spring back. Give yourself a little wiggle room for shoulder bump adjustment with your lapped shellholder.
bigedp51
fguffey said:
1. The SAAMI has nothing to do with the military chamber on the M1917 Enfield rifle. (or any military rifle) The Military 30-06 chamber is larger in diameter and longer in headspace than SAAMI "guidlines".
2. All SAAMI dimensions are from the bolt face to the datum point and the base of the case to the datum point. Please show me the "datum/shoulder to the case mouth" dimentions in the SAAMI drawing below. :
3. And what does 2.494 -.020 mean about case length below.
4. What does GO and NO-GO gauges have to do with shoulder location. ???
4. Buy a WFT case trimmer and tell me what your case lengths are.
Just cut the bottom of the die. Or if you have as savage make the head space longer.
Larry
Larry
savagedasher said:
I tried to with a bastard file with 0 luck. Stuff is bookoo hard, haha. Getting some sandpaper this afternoon for the shell holder.
The die is the way I do it with a grinder. Larry
Took .006 off the shell holder with the carbide sandpaper and got a .015 bump. Thanks fellas.
DCRYDER
Silver $$ Contributor
I hope you meant that you got .0015" bump. Otherwise you should have been able to get a .009" without modification.
Catshooter......when did trim length EVER get measured from the shoulder to the mouth? Trim length is from the base to the mouth, so if the chamber is .010" short then you need to trim .010" short. If you start jamming that mouth of the case into the end of the chamber (which is essentially a PERMANENT crimp) then someone is probably gonna lose any eye if not their whole head.
Catshooter......when did trim length EVER get measured from the shoulder to the mouth? Trim length is from the base to the mouth, so if the chamber is .010" short then you need to trim .010" short. If you start jamming that mouth of the case into the end of the chamber (which is essentially a PERMANENT crimp) then someone is probably gonna lose any eye if not their whole head.
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