Case stretch anyone measure for it?

adccoyote428 · Dec 25, 2015

Was wondering if anyone else measures with a Hornady head space tool with new brass and then fired to see case stretch? I am getting .006-.007 stretch with new brass and then fired it seems my chamber is short because many will not allow bolt to close up if. I try to neck size after one firing so use Redding S FL die and bump back .002 and then they all fit.

Using Nosler brass and not hot loads in a 6.5 Creedmoor, my .243 I can fire 2-3 times prior to having to bump shoulder back.

kraky1 · Dec 25, 2015

Absolutely. ...it's great tool. If you ever play around with belted Magnum cartridges you'll really be surprised. It's not unusual at all to see growth of at least .020 in.
I have a little Cva scout rifle thats a single shot break action in a 7mm 08. It was driving me crazy with four to five inch vertical groups at 100 yards. After pulling my hair out for a year or so with that gun I finally figured out that even mid-level loads were expanding the case back and It was pushing on the frame while the case was also being held in place by the chamber. I found if I push the shoulders back to virgin dimensions and made the charges mild enough that it couldn't come back that far it became a really awesome shooter. I have to throw the shells away after three reloading otherwise I'll crack em above the base but I didn't buy it as a plinker . Not sure i ever figured all this out without the hornady headspace tool.
It's also a must-have if you play around with range brass.....or... you need to convert from one cartridge to another like I often do with 308 - 7 mm 08, or 270 win to 2506.

Kodiak · Dec 25, 2015

I check ALL cases, even new ones for length. Nosler brass is usually short a few 1000s, but some major brands can be long, even when new. And may stretch upon firing. It is possible for different rifles to require fl resizing and others to need less resizing, in order to fit the chamber properly.

This keeps us reloaders on our toes!

adccoyote428 · Dec 26, 2015

Yes I see some neck stretching in the 6.5 but mostly at the datum line. Yes love the Nosler brass just more consistent in the 6.5 Creedmoor to me than Hornady.

With Nosler brass being shorter just means I trim less often on necks but FL resize to move that shoulder back after each load.

I write down the datum line measurements and compare them after being fired, just more information to have on hand and know where my shoulder bump should be.

nvbroncrider · Dec 28, 2015

After first firing I neck size only unless I have chambering issues. When you neck size only after firing to the chamber you get less stretch. Some calibers are inherently prone to stretching such as a 22-250 243 300 H&H others are not such as 6.5-284 280AI. The cases with sharp shoulders and minimal body taper strech less. Those with shallow shoulders and more body taper strech more. Another way to reduce case strech is to set your FL dies up to just bump the shoulder back .001-.002 if it will still allow you to properly chamber the case afterwards.

ElmerThud · Dec 28, 2015

I use the Hornady Headspace tool, also the RCBS precision micrometer. Both excellent tools and allow me to full length resize fired cases to exact 'fired case headspace dimension'. It's pretty straightforward to set the F/L die to exact resizing and work to +/- .001"
I never have chambering issues.

Brand new cases rarely match the fired case dimension in my rifle so firing new 'waste' rounds is a chore. Although new brass loaded with my sweet recipe is accurate, the impact point is different until the brass is resized to the correct headspace dimension for my rifle.
Cheers, ET

Kodiak · Dec 29, 2015

Sometimes when we FL resize fired cases, we still find some resistance to chambering a loaded round. If your die is touching the shell-holder and you still have problems, carefully remove a few 1000s from the top of the shell-holder, and screw the die down a little . This may also bump the shoulder, so caution is the word.

YMMV

adccoyote428 · Dec 29, 2015

Yes talked with a USA team F class shooter and he has given up on neck sizing all together a few years back and he says by shoulder bumping .002 your stretching is about as non existent as neck sizing plus you know they will all chamber.

I use Redding S series dies and since switching to them I have found them to be super consistent and he recommends I anneal brass for longer case life. Will try some annealing in the near future. Have some Tempilaq and a torch.

ElmerThud · Dec 30, 2015

adccoyote428":15yunlgi said:
anneal brass for longer case life.

Doing this certainly works. Also, it tends to even out the elasticity of brass cases at the neck. My findings are the use of a Lee Factory Crimp Die, although an extra operation, further aids consistent neck tension and as a result lowers ES when checking muzzle velocities using a chrono.

All these factors may help produce good consistent ammo, but does depend on how anal one wants to get.
Cheers, ET

lhsako · Jan 4, 2016

nvbroncrider":1z2z9fit said:
After first firing I neck size only unless I have chambering issues. When you neck size only after firing to the chamber you get less stretch. Some calibers are inherently prone to stretching such as a 22-250 243 300 H&H others are not such as 6.5-284 280AI. The cases with sharp shoulders and minimal body taper strech less. Those with shallow shoulders and more body taper strech more. Another way to reduce case strech is to set your FL dies up to just bump the shoulder back .001-.002 if it will still allow you to properly chamber the case afterwards.

>>> I do this too. use new brass for hunt loads only. all shoot the same. I DO run each round thru the chamber even w/ the new brass to be certain the chamber properly.