Need help with COL and bullet jump...setting my dies for the first time...ARG!!

kilohertz

kilohertz

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HI guys,

A great learning day yesterday, although frustrating..setting up my Dad's Dillon 550B for the first time. I have used it in the past but he had all the dies setup already, all I did was sit down and go.

Anyway, I am starting with 7x57 and have FL RCBS dies and have them all mounted in the tool head, depths set and all that is fine, de-priming and sizing work fine and look and measure fine, problem I'm having is figuring out where to seat the bullet. I have read through numerous manuals on the subject, and perhaps I am placing too much importance on this and should just start with the factory COL (3.065"), but I am the kind of person that likes to do things once, and do them right....so....

What I have done is resized a case, inserted my starting bullet, a Hornady 175gr RN, and seated it about .25", loaded in the rifle and tried to chamber it, wouldn't go, so seated a little further, 1 turn at a time on the seating depth screw, until I could close the bolt. When I pulled it out, turns out it was at a COL of 3.25"...huh? Tried it again and maybe I'm not doing it right but this time it was at 3.17", next time was 3.11". ARG! I tried marking the bullet tip with a sharpie to see where it is contacting and can't see anything...so after toasting 6 cases and bullets, I gave up and came in.

So here I am...asking how YOU find your distance to the rifling and what the heck am I doing wrong. I only have 20 7X57 brass right now and I don't want to screw up any more. :(

I also have 3 other bullets to do this for...so I need a reliable method. Once I have the right COL for each, I can store the finished dummy rounds and reset the seating die each time for each bullet.

Thanks guys!
 
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3.025 is the correct length for a 175.
Forget the seating off the lands thing until you have a load. It's a target load tweaking thing. However, put the bullet in the case mouth by hand and chamber. The rifling should push the bullet into the case, then you seat it about 20 thou more.
Those 6 are not toast either. Buy a kinetic puller(That's the hammer style.) and go find a nice rock.
 
Thanks for that info. I have also been reading a lot more this AM and head is just swimming..I am going to have a break for a while....

Well, I do have a puller, but it's 400km from here right now...need to get it shipped. I'll just keep the dummies until I get the puller here.

thanks
 
Well after more reading and with another cup of coffee in me, I went out to the shop and tried again..and this time I got it. I used one of the split cases from my cull pile and pushed in a bullet part way, smoked it with a flame and loaded it...came up with a consistent 3.250", tried it multiple times and each time within .002". Good enough. Then I set the die to move it another .030". It doesn't look right and I could use some guidance. Is this safe or is this one of those times you put the theory out the window and seat it a common sense depth? The 139gr obviously won't work at this depth so I will have to seat it further. From what I have read, you should be able to seat it just deep enough to hold it square, load in the magazine correctly and have them chamber properly. Am I missing anything?

Also, does this case look okay after the resize? It looks like the neck isn't getting resized right down to the shoulder. The way the RL550 shell plate holder works, I already have the die touching it.

Thanks all.

DSCN4783.JPG


Top, once fired, bottom, resized.
DSCN4780a.JPG
 
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Some people insist on loading their bullets .035 off the lands. IMHO, that is a good place to start.

Resizing all the way down to the shoulder isn't necessary. Especially in your case where the chosen bullets aren't seated deep enough to make a difference. By only partially resizing the neck, the bit of neck that isn't resized will give a bit more support and keep the rest of the neck centered in the chamber. Not that it is needed in this case but every little bit helps.

The 7x57 case has a reasonably long neck and holds the bullet relatively well until it enters the leade when fired. This is a good thing, especially when using boat tail bullets.

Back when the cartridge was first conceived, the trend was to long necked cases so that the bullets could be held straight while being fired so they could enter the leade true.

This was and still is a good idea. That's why, for the most part, deep seating of bullets isn't particularly detrimental to accuracy. Some even believe it slightly reduces pressures. Maybe??? Then again, Maybe not?

If you have a very generous chamber, you will likely want to seat your bullets as far out as you can. Just like you did in your pics. This can cause issues as well because it might lead to crooked bullet seating (not likely though). Personally, I load as far out as the magazine or chamber will allow.

You don't mention the rifle you are using. If it is a milsurp in the model 93-95, it likely has a milspec chamber with a long throat. There was a problem with the 8x57 military bullet developing loose bullets and it was felt this was due to reduced length necks. The 7x57 which was developed a few year later was left as first designed, with a long neck to alleviate this problem.

Good choice of cartridge by the way. In a 98 action or modern rifle it can be loaded to slightly higher velocities than the 7-08.
 
Are you seating your bullets that far out? Like a 1/4" behind the cannelure? To be honest, I'd seat it down to the cannelure to start. COAL helps, IMHO, to ensure that the round will feed through a magazine. Think 30-06, with bullets running from 110 gr to 240 gr. how could they possibly all be used to the same COAL?

BTW, I don't bother reloading for my 7x57; blue box Federal of all things turns out to be MOA in my old milsurp honey. So, if you need brass, PM me and we can probably arrange something.
 
Hi Fellows,

Thank you so much for the detailed replies, glad to get some support here, makes me more comfortable knowing I am at least heading down the right path.

The rifle is a 1971 Voere Kufstein, 2155, 24" barrel, and is a Santa Barbara Mauser K98. I think they used an aftermarket barrel.

Bearhunter, thanks for the details...I was concerned about the pressures in having that extra air space in there, and am not sure how it will affect things but will find out when I get to the range. I am still, and always will be, learning...

ATOM, I haven't actually loaded anything yet...just getting started and got the dies set up today. Yes, my mag is 3.25" long and everything I tried today, fits no problem. I will take you up on your offer and buy all your brass, thx, I need it, as I am just getting started in this caliber. My 175 gr will be seated to a CAOL of 3.20" to start and I will work from there, and GANDERITE, yes, the 139 will be seated a bit deeper as suggested, to at least get it square.

Thanks again boys...really appreciate the guidance.

Cheers
:cheers:
 
Air space in a black powder cartridge is the kiss of death. Not so important in smokeless powder cartridges. Usually the best powder for accuracy and consistency is one that fills the case to the base of the bullet.

The reason it isn't such a problem with smokeless powder is because the coating on the powder is what determines its burn rate.

If you decide to use a ball powder, be sure to switch to magnum primers.

I am not advising you to do this but I use magnum primers for all of my loads.
 
bearhunter said:
If you decide to use a ball powder, be sure to switch to magnum primers.

I am not advising you to do this but I use magnum primers for all of my loads.
Click to expand...

Thanks! I have been accumulating powder for the last few months and have WIN760, Varget, IMR4350 and 4064. Any of these will work, and I have read many threads on various loads of each, but it seems that 760 sort of had the bigger following with great results. Of course, it depends on the bullet weight and I think a lot of those 760 loads were with 139 gr.

thanks !
 
Question Are you over caming when you Size your fired brass? (fired in your rifle?? )

If fired in your rifle brass might or might not give you problems (now but will give you problems in the future)
 
just having some fun said:
Question Are you over caming when you Size your fired brass? (fired in your rifle?? )

If fired in your rifle brass might or might not give you problems (now but will give you problems in the future)
Click to expand...

Not sure what you mean by over caming? The Dillon RL550 is a progressive loader, and the workstation moves up to the dies. I was considering just neck sizing as this is my only 7x57 rifle, but after more reading, it's not a bad thing to full resize and i think I will keep resizing FL.

Thanks
 
For any learning reloaders - don't do what this guy is doing. Think about this bullet jump thing. When the bullet begins to move, it slides out of it's seated place in the case a little - maybe 30 thousandths of an inch and then contacts the rifling as the rear of the bullet is still far into the neck of the case. There is no jumping involved.

The biggest difference is this: When the bullet is touching or almost touching the lands, the pressure spike is sooner and more violent and more radical. This is not a good thing. A five-thou variation in length is very very dangerous when loaded close to the lands

The other difference is this: If the bullet is out too far, it will engage the lands and if the bullet is not shot, it may pull out of the case as you attempt to eject the unshot cartridge. Now you have powder spilling all through the action and getting gummed into any lube - requiring a rod to take the bullet out of the bore and a major cleanup which really messes things up if you are hunting. Another not-good thing.

If you load to spec COL, the cartridge can be safely loaded into any magazine in any gun and trusted for any situation - pressures will be more moderate and accuracy will likely be better than any and all guns that are in your safe.

It would be better if no one mentioned the max COL thing to anyone who is not five years into the sport - it is just not worth the danger and fuss.
 
Anchor, sage advice my friend, thank you. I have determined what the distance to the lands is and I think based on your advice and some further reading, I will just start out with stock COL and work from there. Hell, I can't even shoot a 1" group with my .22". I guess I am being a bit anal with all the detail....it's just I really enjoy reading about this stuff and learning..maybe I'm getting in too deep too fast.

Thanks
 
anchor3593 said:
For any learning reloaders - don't do what this guy is doing. Think about this bullet jump thing. When the bullet begins to move, it slides out of it's seated place in the case a little - maybe 30 thousandths of an inch and then contacts the rifling as the rear of the bullet is still far into the neck of the case. There is no jumping involved.

The biggest difference is this: When the bullet is touching or almost touching the lands, the pressure spike is sooner and more violent and more radical. This is not a good thing. A five-thou variation in length is very very dangerous when loaded close to the lands

The other difference is this: If the bullet is out too far, it will engage the lands and if the bullet is not shot, it may pull out of the case as you attempt to eject the unshot cartridge. Now you have powder spilling all through the action and getting gummed into any lube - requiring a rod to take the bullet out of the bore and a major cleanup which really messes things up if you are hunting. Another not-good thing.

If you load to spec COL, the cartridge can be safely loaded into any magazine in any gun and trusted for any situation - pressures will be more moderate and accuracy will likely be better than any and all guns that are in your safe.

It would be better if no one mentioned the max COL thing to anyone who is not five years into the sport - it is just not worth the danger and fuss.
Click to expand...

Good Advice::agree:
And sometimes on the average hunting rifle seating at or close to the lands will not increase your accuracy.
SM
 
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