7x64 Reloads not chambering perfectly

[nyathi]

I am experiencing a problem with reloading for my 7x64 (a fairly new aquisition) in that all my reloaded ammo needs an extra downward pressure on the rifle bolt lever when chambering each round. When chambering a round the bolt moves forward sliding the cartridge out of the magazine into the chamber normally and the initial locking movement starts normally but the last centimetre or two that the bolt lever needs to move downward is against pressure not experienced when chambering a factory round. (Chambering factory ammo chambers perfectly.) The brass of my cartridges are cut to length, the over all length is shorter than the factory ammo (there is no contact by the bullet on the rifling landing), the resizing and bullet seating is done with the cartridge holder touching the die.

The shooting and spent cartridge extraction is normal - Grouping is good, no pressure problems evident.

I'm convinced that my reloads are simply larger than my chamber indicating a problem with my dies.(the dies are brand new +- 200 rounds) Is there something I'm overlooking ?

Is it possible that the dies that I'm using are incompatible with the make of my gun ?

 

[Glock9]

Most likely the problem is that you sizing die is not adjust down far enough. Where the cartridge neck statrts is probaly a few thousands off.

Best way to tell is with a case gauge.

 

[nyathi]

The shell holder is pushed flush with the die when resizing - lower adjustment is not possible because the whole cartridge is inside the die at the end of the resizing stroke.

I've only measured brass length so far and visualy checked seating depth. I'll try to measure the diameters on the neck - funny enough I've got one of those RCBS verniers somewhere.

 

[USSR]

nyathi,

Try a different shellholder. I had a problem with a Redding body die not bumping the shoulder back enough with the shellholder against the die. I switched from a Lyman shellholder to an RCBS shellholder, and that took care of the problem.

Don

 

[asknight]

+1 USSR, sounds to me like the shoulder needs to be bumped back a thousandth or two.

 

[Big_R]

I agree, it sounds like your headspace on sized cases is a little long. If possible, try using a shell holder from the die manufacturer and see if there's any improvement. Another thing you can try is decap your fired cases using a universal decapping die and size without the decapping pin/expander ball assembly in your sizing die. Sometimes, while removing the case from the sizing die, the expander ball drags on the inside of the case neck, stretching the case a little. Make a round (or a dummy round) this way and see if it chambers easier. If it does, you could try lubing the inside of the case necks or just sizing without the expander ball in the die.

Ryan

 

[nyathi]

I am unable to measure a difference on the position of the neck-"folds" with my vernier.

I must say that the expander does drag heavier than what I'm used to (I also reload for my .375 H&H) on this set of dies - I'm definetely going to try removing the expander and see if it it changes the situation before I buy a new shell-holder.

Say it is the expander and extra lube does the job - any advice on applying the right amount of lube in the case neck everytime ? I've always been wary of overlubing the case-neck thinking that it will change the ignition characteristics in the early ignition stage (varying pressure curve) as well as affecting the propellant ? (Am I being pedantic ?) I've a got this idea in my mind that a droplet of lube inside the cartridge will collect propellant over time and change the ignition efficiency of the collected material which is bad. Then again I'm not a benchrest marksman.

 

[Chawbaccer]

Get some mica or graphite to dip your necks in, you won't have to worry about overlubing that way. Another thing, just setting the die so it contacts the shell holder isn't right, have the press knuckle over when the die hits the shell holder

 

[Big_R]

As for lubing case necks, mica works well, however if you don't have any, put a little of whatever case lube you have on a cotton swab and make a few revolutions through the neck. Remember, you only need to do a few cases to see if it helps. If it does, then I recommend picking up a case neck lubricator setup (they're pretty cheap), but no use in getting one if you don't need it.

Removing the expander ball can make it harder to seat bullets, however if you have some boat tail projectiles, you probably won't notice the difference. Good luck.

Ryan

 

[snuffy]

The advice about knuckling over, or as I've heard it, camming over, is spot on! Just having the shell holder kissing the bottom of the die is NOT enough,,,SOMETIMES. The most important thing is to have the shell holder tight against the bottom of the die when the brass is inside the die and the ram is at it's upper most part of the stroke. Some presses have a positive stop built into the linkage. In those,(lee does this), you have to "feel" when the ram stops, is it stopping against the built in stop, or is it stopping because it's against the die? In cam over presses, adjust the die down until you feel the linkage cam over when the ram hits the die with a shell in it. That will take all the spring and slop out of the linkage.

What I use for inside lubing necks is the RCBS nylon brushes. Just roll them on a lube pad, they pick up a very small amount of lube on the tips of the bristles. Enough to ease the expander button through the neck without stretching it. The RCBS lube I use on the pad says on the bottle it CAN Or it MAY contaminate powder or primers. BUT the tiny amount that's left on the necks shouldn't hurt.

I've begun using the RCBS case slick spray lube for my bulk loading in the dillon 650,(.223). Since the bottle didn't say one way or another about powder/primer contamination, I called RCBS. The lady on the other end said they had tested it 6 ways to Sunday, it did not affect powder or primers! Spraying a bunch of .223 brass in a bowl and shaking them around gets some of the lube inside the necks. Plenty to ease the expander through the necks. No worries about leaving it there!