joe0121
Well-Known Member
Lol getting a question answered around here also leaves you with more questions. which is a good thing means your learning.
Which press?
- Thread starter Coues Sniper
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Back when belted cases were popular for shoulder fired rifles in competition, the most accurate ammo was made two ways.
One was to use new cases. Prime 'em and put in some powder then seat a bullet. Accuracy in Hart and Obermeyer barrels was under 7 inches at 1000 yards. No special setup on the press except running the neck through a die to reform it to hold the bullet tight enough for handling. A recent 1000 yard record was set with a .300 Wby. Mag. with new cases so prepped.
The other way was to use a full length sizing die with its neck lapped out to 2 or 3 thousandths smaller than a loaded round's neck diameter. Set the die in the press such that the fired case shoulder would be set back a couple thousandths so it would headspace on its shoulder. Then use a second body die made from the middle part of a full length sizing die with its bottom squared off well to size the fired case again all the way to the belt. Regular full length sizing dies don't get rid of the ridge a few thousandths in front of the belt on once fired cases. That ridge interferes with perfect and consistant headspacing and has to be sized down to about new case diameter. Larry Willis (Innovative Technologies - Reloading Equipment) now makes a collet die to do this. No other sizing method for fired belted cases consistantly worked as good as this way.
I don't think there's any special set up with dies in a press. I've never used any and got results equalling what benchrest record setters do. 1000 yard groups have a mean radius of 2 to 3 inches with an occasional 5 or 10 shot group that's very tiny. Won my share of long range matches wearing out a few barrels along the way.
No mention what the unit of measurements are for those groups. Inches or MOA at what range? How many shots each? Without some meaningful details, they are virtually meaningless. Especially when all groups measured at the muzzle are zero; both in inches and MOA.
First off, those aren't really even for public viewing, they are my own records, but figured I'd post them.
Second - the Group size is in inches at 100 yards as in .105" at 100 yards
Third - each group was 5 shots with 5 bullets
Fourth - What do you mean measured at the muzzle?
Also here is my load data for my AR-15 also groups measured in inches and 5 shots at 100 yards. AR-15 Load Data <Link
Feel free to critique me more.
(Also if you think about it, .105 is basically the same thing, it's inches or MOA, they are both based of "basically" 1 inch.. but what do I know...)
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The size of the group at the muzzle. It's always zero.
All bullets at the muzzle are dead center in the bore when they clear the crown. Then they start to move off the muzzle axis from forces external to them as well as their own internal centrifugal forces due to their unbalance. Virtually all bullets are unbalanced to some degree but those with the least amount shoot the straightest.
I didn't ignore the rest of your post. You assumed I did but I didn't. I didn't find anything to comment on other than correct your assumption. All that other stuff's fine by me.
No, you don't put the target up to the muzzle. That group at the muzzle is where the bullets start their path at after they leave the muzzle. I mention it because between that place and the downrange target, the bullet strays from the ideal and perfect trajectory to where you aimed it. There was no mention of how far the groups were from the rifle in your earlier post with all the load data.
By the way, your "handle" at the end of your posts should read some amount larger than "1/4 MOA AR-15." That's 'cause the term means the largest groups the rifle fires; they're all that size or smaller. Some of the groups you listed were larger than 1/4 MOA.
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After all's said and done, those groups you shot are pretty darned good for an AR-15. Seeing's how I'm the first person on this planet to shoot the M16 rifle across the standard service rifle course of fire in the USA, I wished those rifles we used back in 1971 would have shot about 1/4 MOA at 100. They were about 1/2 MOA rifles at that range and about 1.5 MOA at 600 yards.
Groups don't subtend the same angle as range increases. That's why I wanted to know what range your table's groups were at. And knowing they all start out at zero MOA, how much they open up each hundred yards down range is important.
Trickymissfit
Well-Known Member
PC's been shot down for the last few days, so I need to catch back up. The tests I did were not perfect, but as best I could do. The Shadowgraph don't lie, and is extremely accurate. One thing I failed to measure was just how strait the case necks were (angle to centerline of body). I could have calculated it down to four digits pass the zero point, and should have. We all took the data and used it to tweek our loading systems (except for one guy). One thing I do remember seeing was a varience in dies at the pressure ring, and this was as much as .0025". Had no basis to compair the 6BR off of, and the guy just wanted to know how well he was doing (he was using a special non cataloged item Redding sizer and seater that was a perfect match for the reamer Ron Pence used to chamber his barrel). I do know that his press had been tweeked a little bit, but whatkind escapes me.
as complicated as it sounds, it was fairly easy to do. Was also a good learning experience
gary
Trickymissfit
Well-Known Member
the real problem is wear in the bore that the ram travels in. If it's got less than .0035", your in great shape. Another major hassel is the machined clearence in the 7/8-14 female thread in the top of the press. Just no easy fix there. And of course the lock nuts (everybody's) leave a lot to be desired. There are some very good precision jam nuts out there, but they'll set you back about $12 a piece!! Avoid the ones that use a set screw to lock it on the thread. The split ones are better
gary
@Bart - I haven't shot at a target over 100yrds as it's the only thing I have right now, looking to shoot at a 200yrd range this year.
@Tricky - My press is a Bonanza CO-AX not a Forster CO-AX, I bought it used, and it's been ran hard so I've heard... So would it benefit me to "upgrade" to a new Forster CO-AX, I can actually see my split Forster locking ring on my die move up and down on the right side of my die as I pull the handle down, I'm shooting VERY good 5 shot groups.... so If I can beat my current groups I'm in for a new press!!
NOTE: I've heard that the more "floating" the better when it comes to dies,etc... Maybe if I marked the case with an up arrow when fired in my rifle, then reloaded it with the arrow pointing at me every time, maybe then I would be ok without a new press? I'm just confused.... I shoot groups people don't believe and I do with with this "worn out" press...
@Tricky - My press is a Bonanza CO-AX not a Forster CO-AX, I bought it used, and it's been ran hard so I've heard... So would it benefit me to "upgrade" to a new Forster CO-AX, I can actually see my split Forster locking ring on my die move up and down on the right side of my die as I pull the handle down, I'm shooting VERY good 5 shot groups.... so If I can beat my current groups I'm in for a new press!!
NOTE: I've heard that the more "floating" the better when it comes to dies,etc... Maybe if I marked the case with an up arrow when fired in my rifle, then reloaded it with the arrow pointing at me every time, maybe then I would be ok without a new press? I'm just confused.... I shoot groups people don't believe and I do with with this "worn out" press...
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Trickymissfit
Well-Known Member
guess you could check the press out to see what slop it has in it. Mine is a Bananza just like yours, and it's sized a lot of long strait walled cases over it's lifetime. The wear will show up in the upstroke under pressure. I doubt that it will show much due to the dual guide rods keeping things aligned. You might want to check the two sets of linkages that raise and lower the ram. You may have one that has more wear than the otherside. One nice thing about Forster is they will sell you individual replacement parts.
Try loosening the lockring clamp screw while it's under pressure, and then retighten it. My slot is very tight on my press, and can be a pain to snap in the lock rings if they happen to be on the wide side of the window. The Lymans are a few thousandths smaller and seem to float better for me. Yet you still need to loosen and then retighten them once the die is under pressure.
gary
