Video On Bump sizing cases.

fguffey

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BUMP! Bump is a function of the press, if the press is not a cam over press there is no bump. And then there is this thing about 'bump back'; how is it possible for the reloaders to bump the shoulder back? I find it is impossible to bump a shoulder back with a die that has full case body support.

I have no problem reducing the length of the case from the shoulder/datum to the case head, again I find it impossible to move the shoulder back.

It wasn't that long ago when the experts were singing the praises of the bench rester. they claimed reloaders should do it like bench resters because bench resters full length sized ever time. And then they realized how there was as much as $2,000 difference in two rifle.

F. Guffey
 

fguffey

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I knew it would work since I've played with particle sizing using full length dies,,, paying attention to the sides of the cases to prevent the squeezing affect,,, the shoulders don't move forward if I get the die set...
You fixed it so the shoulder does not move forward and I say it is impossible to move the shoulder back. We are lucky, no one has a clue.

F. Guffey
 

Don A Parsons

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If I use my Hornady Precision 6.5/06 FL dies using part of the stroke,,, the shoulders on my brass must be moving forward,,, I tried a few adjustments to figure out what was going on with this particular sizing die...

Once I pass a certain point,,, the case walls start compressing that pushes the shoulder forward,,, if I keep turn the die down the worse it became...

The bolt handle with no firing pin won't even get close to closing at that point,,, so I screw it down more so it can bunch up the shoulder so the handle will drop freely,,, the normal use of using FL Dies...

I just tried JE's partial FL die sizing idea and things are working good"""so far."""

The sizing die must not be touching the case walls or just barely touching,,, the shoulder is not moving forward,,, and its sizing part of the neck,,, at least the bolt handle drops free doing it this way...

Like I said on the above post,,, after shooting all 30 cartridges,,, I pulled the firing pin and each case must of sprong-back... free bolt handle drop with no tension...

The best part was a few tight ladder shots at 200 meters with this hunting rifle,,, it sure shoots nice now...

At least I'm not over working the brass which was happening before giving this a try...

Don
 

fguffey

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It seems that it's the neck sizing guys who aren't trying stuff, every guy I know got gains by sizing to get .002 head space also used to neck size.
My cases do not have head space; when I size a case I want to off set the length of the chamber from the shoulder of the chamber to the bolt face. Anything left over is clearance.

Back to moving the shoulder back, it is impossible to move the case shoulder back and then there is Lyman; long before the Internet Lyman said the shoulder moves forward. They also said then the case body begans to be sized the case shoulder moves forward and they said the shoulder takes on an arch appearance. Many years ago I use a feeler gage between the bottom of the die and top of the shell holder to control die adjustment.

F. Guffey
 

Don A Parsons

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Thanks for the heads up Guffey,,, I'm sure thats what was happening... my sizing die must of been set to low for these cartridges...

Things are looking better on paper at the 200 mark,,, another kick at the can at 4 and 600 meters...

Not over working the brass,,, and it fits the chamber like a glove... win win...

I didn't have this problem with my 30/06 or 308 die sets,,, all 4 sets for my 308 are spot on,,,, but this 6.5 A-Square has give me a run for the money over the last 8 months,,, of course I was just winging it till I came across JE's thread...

I was just about ready to drop $300 ish of Cnd funds for a Willson custom sizing die,,, but now I can use what I have,,, $78 for the Hornady Precision die set with the floating centering insert and selection of ball expanders is good enough for this hunting rifle...

I enjoy trying different things with the rifles I'm running,,, a reason to wake up and see what things will look like on paper...

Hopefully the same consistent ladder test as last time,,, then its time to dig out my other tack driver... Ha
 

Don A Parsons

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Lots going down on the partly sized brass using the FL die...

Just pulled off Two ladder test runs on the weekend,,, One ladder at 2",,, the other at 2 1/2" at 400 meters... both 5 shot sets...
Of course I had to plant a fly'er into the mix

Ye Ha,,, pretty thrilled with that out of a 11.9 lb hunting rifle in 6.5 A Square...

I know one thing after doning the Part FL thing,,, chamber each brass with F-Pin removed,,, go with free bolt handle drops.... absolutely no felt tension of the handle or it gets put into the FL brass sizing catagory...

This gives me a chance to test 4 loads... win win...

I have lots of brass for this rifle,,, so I loaded Two 10 shot batches to run at 600 meters...
Left and Right separate ladder test...

Each target at 6' T x 3' W,,, ha if i can get all 10 shots onto the paper that is... 2 sets... total of 20 shots...

What a great way to burn the barrel off this rifle,,, Ha

Don
 
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Don A Parsons

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Starring off with the clean barrel,,, 7 ish to fowl it up a bit,,, room temp then run the first 600m 10 shot ladder,,, hopefully I find a flat line in the mix...
6.5 A-Square,,, 143gr ELD-X,,, 50.2gr to 52.9 of H1000... 2710 to 2980 ft-per second range...

I have a sneaking suspicion that the tighter vertical will be in the 50.2 to 50.8 grains,,, best water-line to date is both the 50.2 and 50.5 grains...

I was challenged to get 1/4" moa up to this point,,, good thing I did the frugal easy brass prep... Fire formed and dirty brass,,, nylon brush the necks leaving the carbon build up,,, then a carbon dip on the necks before seating bullets...

Way less chances of neck to bullet weld,,, and a lot less neck tension,,, very consitent pressure when seating bullets...

If i get this right,,, ill be doing the 1 km shoot this spring,,, I had good success with my 30/06 a few years ago at the 1 km mark,,, 14" or 17" ladder if I recall,,, hopefully i can match or bet it...

20 shots for that run... Ha... Its kind of like checking to see if consistent,,, 10 shots less than a match shoot... Lol

I cant wait to get this rifle sorted,,, then get my range rifle up and running...

14.7 lbs of glory... ha

 

ericbc7

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I have commented on ladder tests in the past and I frankly hate em. So you know where I’m coming from. There are so many vagaries (wind, mirage etc) with a ladder test that I hate to place a lot of weight on them. You can get the same/better info with a chronograph and more reliably. In a perfect ladder test you are measuring velocity and nothing else. Similar bullets of similar velocity will group together...unless you flinch, pull a bad one, mirage tricks you etc. you basically have a series of one shot “groups”. No value for deciding loads.
just load a series of incremental loads and track the velocity. Find the nodes and proceed.
my 2 cents
-Eric
 

ericbc7

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If you don’t have a chronograph and need to use a ladder test to determine velocity nodes, then you should do at least 3-5 shot groups and use the center of those groups to determine nodes.
 

ButterBean

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I have commented on ladder tests in the past and I frankly hate em. So you know where I’m coming from. There are so many vagaries (wind, mirage etc) with a ladder test that I hate to place a lot of weight on them. You can get the same/better info with a chronograph and more reliably. In a perfect ladder test you are measuring velocity and nothing else. Similar bullets of similar velocity will group together...unless you flinch, pull a bad one, mirage tricks you etc. you basically have a series of one shot “groups”. No value for deciding loads.
just load a series of incremental loads and track the velocity. Find the nodes and proceed.
my 2 cents
-Eric
I would have to disagree, I have had excellent SD's and ES"s and velocity nodes with groups that shot worse than lesser SD"s and ES"s and Nodes and what does this have to do with the OP Shoulder bump technique ?
 

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