Do groups open up or get tighter with fired brass?

[AM_Hunter]

I began reloading for my Seekins Element 308. Its my first time doing serious reloading so I am definitely a newbie and could use any insight. Loaded up 25 rounds of Barnes 168gr TTSX in hornady brass with Federal 210 primers and Varget powder. After attempting to load to 0.020" off the lands and realizing I cant fit them in my magazine, I decided to load to maximum cartridge length of 2.200" CBTO and went from there. Loaded 5 rounds ea at 41.5 - 43.5gr and was able to get a very happy group of .56MOA with the 43gr. This is better than I can shoot and im extremely happy with this group, but im wondering if it will open up or get better once I re-use the brass.

Im hoping the group sizing stays the same after I reload with the fired brass as I am hoping I dont have to do further load development. Does anyone have any experience with this?

On another note, I did not know I should chamfer the new brass before loading so the first 25 were loaded this way and I also loaded another 50 at 43grs for 2x 10 shot groups and some dope development. Definitely had some bullet shavings after seating the rounds but after the group I got I thought nothing of it. Will chamfering the cases possibly open the group up or could it only help?

Appreciate the help!

 

[pbroski]

The short answer is that the groups will stay the same. It's one of those things with handloading ammo that would take hundreds of shots with large sample size groups to prove either way.

Chamfering will not hurt, but with that level of precision I doubt you will see an improvement.

 

[northernalpine]

Groupings won’t change, just keep an eye on the length of brass over firings. Soft brass will stretch enough after 1-3 firings you may need to trim, Hornady is one of the brands with softer materials from my experiences.

 

[AM_Hunter]

Groupings won’t change, just keep an eye on the length of brass over firings. Soft brass will stretch enough after 1-3 firings you may need to trim, Hornady is one of the brands with softer materials from my experiences.

I usually trim to SAMI specs during case prep on reloads every time, should I not do that?

 

[northernalpine]

I usually trim to SAMI specs during case prep on reloads every time, should I not do that?

If it needs to be trimmed, trim it, if it’s within spec and chambers in your rifle, load and shoot it. I measure mine after every firing, but usually end up trimming every other just to keep everything consistent. If your process is to trim every time, go with it, there’s no adverse effects.

 

[sdupontjr]

Shouldn't change 1 lick. This is 130 ttsx in my Tikka 308 after about 5 firings of the same load. I do anneal every time. 49g varget, CCI200, 130ttsx loaded at 2.825"

Also, Barnes shoot better at .050" and more off the lands in my gun. Never shot well chasing the lands. If I remember correctly, Barnes even states to start at .050" off lands, but could be wrong. haven't looked at it in a while.

 

[AM_Hunter]

Shouldn't change 1 lick. This is 130 ttsx in my Tikka 308 after about 5 firings of the same load. I do anneal every time. 49g varget, CCI200, 130ttsx loaded at 2.825"

Also, Barnes shoot better at .050" and more off the lands in my gun. Never shot well chasing the lands. If I remember correctly, Barnes even states to start at .050" off lands, but could be wrong. haven't looked at it in a while.


View attachment 734447

Thats good to know, I think I am around .038-.043" off the lands.

On a side note, how fast are your rounds running 130ttsx with 49gr???

 

[sdupontjr]

I don't know but want to check. I'm definitely on the hotter side but that's where My tikka liked it. All were good, but opened up at 49.5. They have 49.2 (max) according to the chart should be 3100 plus. Tikka barrels are usually slower but I figured I'd have to be close to that. At 49.5 I still had no pressure signs, but as you see, groups opened up. And these 130's hit like lightening strikes. at those speeds.

 

[northernalpine]

I don't know but want to check. I'm definitely on the hotter side but that's where My tikka liked it. All were good, but opened up at 49.5. They have 49.2 (max) according to the chart should be 3100 plus. Tikka barrels are usually slower but I figured I'd have to be close to that. At 49.5 I still had no pressure signs, but as you see, groups opened up. And these 130's hit like lightening strikes. at those speeds.

View attachment 734911View attachment 734912

Looks like you're right on the money anywhere in the 47.5-49gr range, the difference in those groups is just likely to be shooter-related as it is powder charge.

 

[sdupontjr]

exactly. The gun and load will shoot better than me, thats for sure.

 

[Safety_3rd]

I want to throw my two cents in here because I’ve had a different experience. I reload and admittedly shoot most of my stuff through a bolt action. On my more accurate rifles 6bra and 6.5 creed for example, it’s not so much my group size that tightens up, but my velocities and SD. I usually only neck size for my first two reloads. I Aneel and trim if needed but generally after the first reload I don’t need to until the 3rd. I also full case resize every third reload. The case expands when it’s fired (no shit lol) and fills the chamber to that specific rifle. When I neck size I’m only resizing the neck and the second time I load that round it almost fits that chamber perfectly, and the neck tension is more uniform between all loaded rounds. An additional benefit of the way I do it, is that the brass doesn’t get as “worked.” And I’ll get 10 reloads on my brass before I replace it. I probably could get more, but I generally replace my brass when I replace my barrel. I should create an excel sheet with my data, but I’m lazy.

 

[AM_Hunter]

I want to throw my two cents in here because I’ve had a different experience. I reload and admittedly shoot most of my stuff through a bolt action. On my more accurate rifles 6bra and 6.5 creed for example, it’s not so much my group size that tightens up, but my velocities and SD. I usually only neck size for my first two reloads. I Aneel and trim if needed but generally after the first reload I don’t need to until the 3rd. I also full case resize every third reload. The case expands when it’s fired (no shit lol) and fills the chamber to that specific rifle. When I neck size I’m only resizing the neck and the second time I load that round it almost fits that chamber perfectly, and the neck tension is more uniform between all loaded rounds. An additional benefit of the way I do it, is that the brass doesn’t get as “worked.” And I’ll get 10 reloads on my brass before I replace it. I probably could get more, but I generally replace my brass when I replace my barrel. I should create an excel sheet with my data, but I’m lazy.

Thanks for that info

Im still pretty new to reloading so im a little confused on the difference between full length resizing and just neck resizing. From what ive learned full sized resizing brings the brass back to SAMI specs, essentially negating any fireforming done right? But if you resize only the neck then the brass stays fireformed to your chamber? Is that right?

If so, do you need a different die for neck sizing?

 

[Safety_3rd]

Yes and if you’re shooting from an AR platform, I’d keep full length resizing. An AR platform, chambers differently and extracts differently (sometimes if it’s over gassed it will really dent the brass neck when it’s ejecting) but it’s not quite as accurate as a bolt action. I wouldn’t waste your time neck sizing. Just keep doing the full length. Aneeling is good to do, and if you’ve got a good set up you should do it between each reload. But if you’re just getting started you can get away with not Aneeling for a few reloads. I would shoot Hornady brass initially while you’re learning then get some Lapua or Alpha brass with small rifle primers. You’ll have to change your load up a little, but I’d rather learn on cheaper Hornady brass then expensive shit

 

[AM_Hunter]

Yes and if you’re shooting from an AR platform, I’d keep full length resizing. An AR platform, chambers differently and extracts differently (sometimes if it’s over gassed it will really dent the brass neck when it’s ejecting) but it’s not quite as accurate as a bolt action. I wouldn’t waste your time neck sizing. Just keep doing the full length. Aneeling is good to do, and if you’ve got a good set up you should do it between each reload. But if you’re just getting started you can get away with not Aneeling for a few reloads. I would shoot Hornady brass initially while you’re learning then get some Lapua or Alpha brass with small rifle primers. You’ll have to change your load up a little, but I’d rather learn on cheaper Hornady brass then expensive shit

Why small rifle primer vs large rifle? Im currently using federal 210 primers, got a few hundred left.

 

[Safety_3rd]

Primer pockets get looser with subsequent reloads and I’ve just found better longevity with the smaller primers. Some hunters in cold weather say that it’s better for the large rifle primer, if that’s something you’re concerned about. Shoot what you have, nothing wrong with large primers. Small are just my preference.

 

[Harvey_NW]

Im still pretty new to reloading so im a little confused on the difference between full length resizing and just neck resizing. From what ive learned full sized resizing brings the brass back to SAMI specs, essentially negating any fireforming done right? But if you resize only the neck then the brass stays fireformed to your chamber? Is that right?

It will only size it back down to SAAMI spec if you set it up that way and smash it back down. Ideally you want to fireform the case to the chamber, then bump the shoulder back .002" with a FL sizing die, confirming with a headspace gauge by measuring at the shoulder datum, or chamber checking. If you really want to get technical you can use competition shellholders with different thicknesses to achieve the "cam over" feel at the top of the stroke, but I've never needed to and get consistent bump using adequate lube.

Neck sizing is a theory of the past and has pretty much been universally ruled out as a benefit, because the brass continues to change dimension, and without sizing the lower portion of the body there's less room for expansion and contraction so it can cause pressure. Bumping shoulders with a FL die typically doesn't work the brass enough to worry about before primer pockets will blow out, especially if annealing. FL sizing just keeps things consistent.

If so, do you need a different die for neck sizing?

Technically you can neck size in a FL die, just don't screw it down far enough to bump shoulders.

 

[AM_Hunter]

It will only size it back down to SAAMI spec if you set it up that way and smash it back down. Ideally you want to fireform the case to the chamber, then bump the shoulder back .002" with a FL sizing die, confirming with a headspace gauge by measuring at the shoulder datum, or chamber checking. If you really want to get technical you can use competition shellholders with different thicknesses to achieve the "cam over" feel at the top of the stroke, but I've never needed to and get consistent bump using adequate lube.

Neck sizing is a theory of the past and has pretty much been universally ruled out as a benefit, because the brass continues to change dimension, and without sizing the lower portion of the body there's less room for expansion and contraction so it can cause pressure. Bumping shoulders with a FL die typically doesn't work the brass enough to worry about before primer pockets will blow out, especially if annealing. FL sizing just keeps things consistent.


Technically you can neck size in a FL die, just don't screw it down far enough to bump shoulders.

Damn I still got too much to learn. Dont know if I need to do that quite yet, especially for my hunting rifle. Ill have to see what kind of groups I get with my reloads once im through my new brass and start using the reloads. If they maintain the .56 MOA I think ill stick to what is working lol. Appreciate the info!

 

[Castle Rock]

It will only size it back down to SAAMI spec if you set it up that way and smash it back down. Ideally you want to fireform the case to the chamber, then bump the shoulder back .002" with a FL sizing die, confirming with a headspace gauge by measuring at the shoulder datum, or chamber checking. If you really want to get technical you can use competition shellholders with different thicknesses to achieve the "cam over" feel at the top of the stroke, but I've never needed to and get consistent bump using adequate lube.

Neck sizing is a theory of the past and has pretty much been universally ruled out as a benefit, because the brass continues to change dimension, and without sizing the lower portion of the body there's less room for expansion and contraction so it can cause pressure. Bumping shoulders with a FL die typically doesn't work the brass enough to worry about before primer pockets will blow out, especially if annealing. FL sizing just keeps things consistent.


Technically you can neck size in a FL die, just don't screw it down far enough to bump shoulders.

As is usual here I disagree with most of what Harvey posted

Plenty of ways to skin a cat

He has done some stuff, I have done some stuff

I pretty much never do anything but neck size with results that can’t be denied

This nonsense about bumping shoulders 2 thou or whatever only works properly with specific shoulder bump dies and people who try to replicate that with standard dies run into so many problems due to the body of the brass being squished and growing longer that they wreck good brass prematurely

 

[JGRaider]

As is usual here I disagree with most of what Harvey posted

Plenty of ways to skin a cat

He has done some stuff, I have done some stuff

I pretty much never do anything but neck size with results that can’t be denied

This nonsense about bumping shoulders 2 thou or whatever only works properly with specific shoulder bump dies and people who try to replicate that with standard dies run into so many problems due to the body of the brass being squished and growing longer that they wreck good brass prematurely

Couldn't agree more. Not sure why some have to complicate the issue. Use rifle specific brass, neck size only with Lee collet die, and repeat until the brass won't chamber in your rifle. At that point you may need to trim, bump, etc. Makes super consistent, accurate ammo.

 

[Harvey_NW]

This nonsense about bumping shoulders 2 thou or whatever only works properly with specific shoulder bump dies and people who try to replicate that with standard dies run into so many problems due to the body of the brass being squished and growing longer that they wreck good brass prematurely

It works just fine with standard FL dies, shooters have been doing it for decades. There is no "specific shoulder bump die", unless that's what you consider a match bushing die without a bushing in it, which would just add another unnecessary step. The majority of competition shooters wouldn't be FL sizing if it didn't work and make more reliable ammo.

Couldn't agree more. Not sure why some have to complicate the issue. Use rifle specific brass, neck size only with Lee collet die, and repeat until the brass won't chamber in your rifle. At that point you may need to trim, bump, etc. Makes super consistent, accurate ammo.

Oh, so you fire the brass until it won't chamber in your rifle, then bump? Weird, almost like I said that is exactly the reason to just FL size and bump the shoulders every time to get consistent ammo.. You also "dOnT gIvE a RaTzAsS aBoUt" anything anyone tries to explain to you, believe in 3 shot groups, and prefer shooting 200lb mammals with a mono out of a 30 cal.

Damn I still got too much to learn. Dont know if I need to do that quite yet, especially for my hunting rifle. Ill have to see what kind of groups I get with my reloads once im through my new brass and start using the reloads. If they maintain the .56 MOA I think ill stick to what is working lol. Appreciate the info!

Hornady headspace gauges are cheap and handy, but you can chamber check as I said in my original response. Chamber fired brass and find one with resistance, screw the die in 1/10th of a turn at a time and size the case until it chambers smoothly, lock the die down and that's your setting. But I prefer to measure.

I'll leave you with this- which is more complicated; dealing with potential clickers and wondering when you WILL need to bump and FL size, or fireforming brass and setting up a FL die once to resize for the life of the brass? I'll also note, some people on this forum are notorious for being extremely objective of other peoples methods because it's not their way, regardless of how much evidence or how many modern shooters have moved on from ineffective theories from the past. YMMV.