Shoulder bump

[BoydAllen]

I dont think id go that far. Some may but most never hit the shell holder.

The reason that the top of the die, including the shoulder, was cut off was so that he could size the base of the case more without bumping the shoulder. That was handled by his regular FL die. The cut off die was used as an additional step. I should have been more clear about that. You can run into a situation with belted cases where setting the die for the correct shoulder location can leave a band above the belt unsized. If the loads are of average pressure this may never be a problem but with softer brass and/or hot loads it can.

 

[Bart B.]

You can run into a situation with belted cases where setting the die for the correct shoulder location can leave a band above the belt unsized. If the loads are of average pressure this may never be a problem but with softer brass and/or hot loads it can.

Exactly; well said. If that ridge is high enough to interfere with cases pushed full into chambers by firing pin impact, it effects how bullets exit the muzzle at the same place in their vibration cycle. New cases oft times shot bullets more accurate than resized ones.

 

[Dusty Stevens]

Exactly; well said. If that ridge is high enough to interfere with cases pushed full into chambers by firing pin impact, it effects how bullets exit the muzzle at the same place in their vibration cycle. New cases oft times shot bullets more accurate than resized ones.

Firing pins making brass jump the extractor again?

 

[Bart B.]

Firing pins making brass jump the extractor again?

No. No. A thousand times no. If they did, case extraction could be difficult.

None of my bolts' extractors ever let case rims jump them. Case rims never made it to the extractor until bolts opened to extract the fired case from the chamber. The cases stopped against the chamber headspace point and fired before case rim touched the extractor. Sometimes setting the shoulder back a few thousandths.

There are no rifle bolts I know of that their extractors hold case heads against and touching bolt faces and stay there when the round fires regardless of case headspace being less than chamber headspace.

I'm not talking about extractors pressing case rims against the bolt shroud opposite the extractor at a right angle to cartridge long axis, there's still a clearance from extractor lip/claw to case rim on the cartridge long axis.

That clearance is typically greater than case head clearance to bolt face.

There are simple ways to measure how much clearance case rims have to bolt faces and extractors when the action is cocked on a chambered round or when the firing pin fires the primer.

 

[muleman69]

Im so lost but enjoy every minute of this, hopefully not to old to learn. I will try and keep up....lol

 

[Bart B.]

Im so lost but enjoy every minute of this, hopefully not to old to learn. I will try and keep up....lol

Remove the bolt from a rifle, slide a case rim into the bolt behind the extractor, press the extractor back towards the bolt face as far as possible then see how much clearance there is for the case rim to freely move back and forth between bolt face and extractor claw or lip.

Or use feeler gauges to measure that space on the bolt then measure case rim thickness with calipers. Note the difference.

 

[fyrewall]

Yes, small base dies can maintain headspace as well as conform brass to intended factory dimensions, like body diameter close to base.

I have not had a need to use small base dies until I got into processing bulk amounts of once fired .223 brass to make .20 Practical. Being driven to make ammo for the least cost, I use once fired .223 but some cases have been fired in semi-autos having sloppy chambers and need to have both headspace & body diameters restored to factory dimensions.

If I don't run the brass through a small base die some rounds have insufficient head-space resulting in difficult to close bolts and some rounds chamber but stick inside the chamber after firing. My Redding small base die fixes this. My .20P rifles have tight match chambers and I like ammo having minimum headspace and should the need arise I use a ground down shell holder to make for adequate head-space vs. no head-space.

For belted head rounds, like my .300 WM varmint rifle, I use a .010 feeler gauge between shell holder & die bottom to ensure the round head-spaces on the shoulder vs. belt - real easy bolt close with a tiny amount of resistance. This gives some indication of the value of a belt on cartridges - I don't have a .375 H&H or .300 H&H.

All my rifles have non-rotating claw extractors and brass rims easily fit between extractor and bolt face..

 

[Bart B.]

For belted head rounds, like my .300 WM varmint rifle, I use a .010 feeler gauge between shell holder & die bottom to ensure the round head-spaces on the shoulder vs. belt - real easy bolt close with a tiny amount of resistance. This gives some indication of the value of a belt on cartridges - I don't have a .375 H&H or .300 H&H.

I've always got best accuracy when bolts closed in battery without any resistance.

Sierra Bullets' tests in the early '50's showed a small loss of accuracy when bolts did not freely close. The bolt head wasn't in the same position for every shot.

Benchrest folks bumped their neck sized cases shoulder back a couple thousandths when bolts stopped freely closing.

 

[cw308]

I'm shooting a 308 , tried the Redding S Type bushing dies for setting neck tension , didn't work out for me , My runout was much higher . Found using the standard RCBS F/L Sizing die with the Redding competition shell holder set of 5, I can set case headspace from zero to .002 with no problem . The standard shell would oversize if setup with die touching shell holder . Not with the Comp. set , set from shell holder to die contact . Never sized belted cases . I also wet tumble using SS Pins , size with RCBS case lube then back in the tumbler to remove lube , then Redding dry lube inside of necks.

 

[cw308]

Bart B
Missed you on TFL , you always gave excellent advise . I'm still using the same Rem 700 308 sizing with the Standard RCBS F/L Die and Redding competition shell holder set . Changed the barrel since the last time we spoke to a Rock Creek M24 5R 11.27 twist . Great shooter my one an only rifle . Hope all is Well.

Chris