.308 Brass - The Second Go Around

[tnichols]

My brass started life as once fired (in my rifle) Black Hills Match (Win). They were prepped, trimmed (2.005), reloaded, and have been fired. After sizing, they are now running 2.008 in length. After reading other threads here, I know that I would not have had to trim back to 2.005 the first time, but what's done is done. So, if I load this lot of brass at the length they are now will a see a POI shift due to slightly different neck tension? I don't want to change a variable as this load is shooting half MOA out to 600-700 yards, which is good enough for me. I also don't want to trim cases back again 'cause it's a pain. What do you guys think?

Rifle: Savage 10FP 26" barrel McMillan stock
Load: 175 SMK over 45.4 grains of RE15 GM210M 2678 fps

 

[CST]

Re: .308 Brass - The Second Go Around

I've usually let them grow to almost 2.015 to even 2.020 when I get lazy and still hit 1000yards. YOur going to bevel the edge of the brass neck anyway...have to account for that not really contributinf to the neck tension.

 

[groovebus]

Re: .308 Brass - The Second Go Around

I neck size them after I shoot it the first time around. Never have to trim. I've been using the same 250 cases for 2 years with no problem. All of them are formed to the chamber of my Savage 10FP LE1. Very consistant out to 600yards.

 

[CK_32]

Re: .308 Brass - The Second Go Around

Honestly I think its all personal preference like it is with half of the reloaders here.. Some things a lot of people are eh it will work.. And then you get that batch of It must be exactly spec.

I've heard of guys running to something ridiculous like 2.075 or more.. I personally let it get to about 2.015 or some where around there then trim back to 2.005.

I wouldnt worry too much about it.

EDIT: Crappy speller sorry

 

[Grump]

Re: .308 Brass - The Second Go Around

Run the numbers, dude!

You probably have at least 0.30 or so of case neck engagement on the bullet's shank or driving band or whatever you want to call it.

.003 off of that? Hmmm... *EXACTLY* 1% change in surface area of engagement.

Even assuming, WHICH WOULD BE WRONG, that the 1% reduction in neck engagement = a 1% reduction in bullet pull resistance = a 1% reduction in velocity (do you see some "tolerance stack" here that's stoopid?), that would still be a whopping 26 or 27 fps change, only compared to the cases on the prior firing, but canceled out by the fact that ALL the cases in the batch are the same.

Quit worrying and just load and shoot!

 

[300ATT]

Re: .308 Brass - The Second Go Around


+1 quit worrying and just load and shoot ...

I doubt that you will notice a difference; however, if you can prove empirically that the POI changes across more than 20+ rounds or that a slightly shorter/longer neck can't hold 1 MOA, let alone 1/2 MOA you might have something to worry about.

 

[42769vette]

Re: .308 Brass - The Second Go Around

i think the main diffrence it will make is piece of mind. so is the piece of mind worth the effort

 

[1Sg (ret)]

Re: .308 Brass - The Second Go Around

Do what gives you confidence.I trim one time to uniform a lot and load till it gets back to 2.015.

 

[RTH1800]

Re: .308 Brass - The Second Go Around

I would get a Sinclair chamber lenght gauge. Simple and cheap. Then keep them within the cham and fairly uniform. JMO