Does this look good to go?

[1S2K]

After 20 years since my last reloading activity, Ive come back to it again with something of a passion...at least in the preparation part of it. I really want to load for accuracy/precision for target/hunting purposes. At 68, I intend to spend as much retirement time as possible shooting. I do have a specific question.
I'm beginning to work up first loads for my .308 Rem 700 and am at the brass resizing step now. I want to know if you think the measurements I have are good to go on to the next step?
Here are a few measurements from Winchester cases as measured with the Hornady Comparator set:
From base to case shoulder on factory loaded case: 1.618"
From base to case shoulder on fired case : 1.620"
After full length resizing for minimum shoulder bump: 1.619" is the new base to shoulder length.
The average case length after one firing is 2.010" then
Average case length after re-sizing is 2.018"!
The measurements from base are to the datum line on case shoulder.

Would you bump the shoulder another .001"? (The fired, un-sized case re-chambered with no difficulty at 1.620".)
Is the .018" case- stretching a bit extreme or is this normal?
The max case length for the 308 is 2.015", so what would you trim to: the book trim-to length of 2.005", or somewhat less than that( maybe 2.010")? I guess I question whether this is working the brass too much.

Thank you for your help here. I'm kinda obsessive about measurements and sometimes that is a real pain. A friend helping me build a shed once asked me "Are you trying to build a shed or a wrist watch"? Kinda sums it up I guess.
Thanks again for any help.

 

[Rtheurer]

First off good for you... Enjoy the retirement sir.

Keep in mind sometimes a cartridge takes two to three firings to fully reach its max size inside your specific chamber. So if your 1.620 chambers easy your not there yet. No need to set that shoulder back if your not at max size. If you can just size the neck until your brass showes signs of chambering hard then thats when you need to start looking at setting the shoulder back and then is when your die will be set and set correctly. Im sure you wil lget some good advice instead of my ramblings. On a match rifle ( not Bench Rest) I set my shoulders back .015 to .02 which seems to chamber real nice with no resistance on the bolt. In a gas gun ill go another .001 to .003 to make sure they will feed well with no issues. Hunting rifles get just over .002 also.
If your shoulder ends up being 1.630 I would set it back to 1.620 to 1.610

Hope this helps.

RussT

 

[drumcorpschamp]

Russ,

I made changes in red. Were those the numbers you intended? If not, I'll just go back to work and stop forum surfing!

Jerry

First off good for you... Enjoy the retirement sir.

Keep in mind sometimes a cartridge takes two to three firings to fully reach its max size inside your specific chamber. So if your 1.620 chambers easy your not there yet. No need to set that shoulder back if your not at max size. If you can just size the neck until your brass showes signs of chambering hard then thats when you need to start looking at setting the shoulder back and then is when your die will be set and set correctly. Im sure you wil lget some good advice instead of my ramblings. On a match rifle ( not Bench Rest) I set my shoulders back .0015 to .002 which seems to chamber real nice with no resistance on the bolt. In a gas gun ill go another .001 to .003 to make sure they will feed well with no issues. Hunting rifles get just over .002 also.
If your shoulder ends up being 1.630 I would set it back to 1.628 to 1.627

Hope this helps.

RussT

 

[Rtheurer]

Ha! Yep what he said.... oops.

That would have really been shoving it back. Thanks.

RT

 

[itchyTF]

For trimming, I would measure your chamber and trim to maybe .010 less.

 

[jonbearman]

I would trim to 2.010 at least and fire to get the cartridge case to fill out in your chamber.I always trim after sizing and I trim no further than .005 under max and as you shoot to form it will end up almost at the sammi spec.What loads are you using and which model remmy is it?

 

[BoydAllen]

A couple of things: Take one case, and fire hot but safe loads, neck sizing only, until the head to shoulder dimension stabilizes, and do your bumping from that dimension. Another usable strategy is to set your die so that shoulder to head is the same as the fired brass, if that brass chambers easily. Based on top benchrest shooters advice, keeping cases trimmed close to max offers no advantage. Case lengthening from FL sizing comes from reduction in the diameter of the body of the case, and shoulder bump. Check your fired brass's diameter at the shoulder and .3 up from the head, and compare it to sized brass. I would like to know the reduction in diameter at these two points. Always reseat (well below flush) or remove primers when measuring head to shoulder on fired brass. You may have some variance in shoulder bump that results in different bolt close feel. There are several steps that you can take to help this situation, but for now, if you want to work with a more uniform figure, resize the cases that come out longer in this dimension with a slight die adjustment, to make them come into line with the other cases. What kind of FL die do you have?

 

[1S2K]

Thanks to all for the helpful input. Now for some of the requested specs:
I am using RCBS competition dies (wanted Redding but out of stock)
This is a Rem 700 SPS Tactical model in 308 (20 inch barrel). I have another 700 with the 5R barrel but haven't started reloading for it yet; and it shoots easy half moa groups with Fed GMM using 168gr SMK's. I don't know if I can improve on that much; but will roll my own for it when I'm out of factory rounds.
As to the measurements requested by BoydAllen:
Measured .3 from the head: fired brass is .470"; re-sized brass is .463"

I meant to put in earlier post that the Fed GMM with 168 gr. SMK length from base to ogive measures 2.224" on average.
Using the Hornady Comparator, and seating the same bullet to the lands in this rifle measures 2.138"! So, the factory stuff is actually jamming .086"???? It chambers fine but does require a little more pressure on the bolt handle to do it. Very little though. I will back off the factory seating depth aboout .020" and see how that shoots.

Could this mean I actually have a Remington chamber that is a little on the short side? That is a first for me.

I really appreciate all the feedback. There are no other reloaders in my area to my knowledge, so its good to "talk" to some pros about this.

As to measurements at shoulder, I measured on the datum line as best I could with calipers(its all I've got). On a fired case, that measurement is .456". On a sized case it is .452".

 

[BoydAllen]

The shoulder measurement that I asked for would be on the OD of the shoulder, right where the radius begins. Your datum line should be a circle part way up the shoulder. A quick check tells me that it is .400 in diameter. It has nothing to do with this particular measurement. Your die is reducing your cases quite a lot. A custom die, such as Neil Jones makes might reduce the diameter of your cases by around .001 in both of the places that I mentioned.

 

[1S2K]

My error on use of terminology...the measurement I took was on the case at the point were the radius begins and not on the datum line as I incorrectly stated in previous post. It appears that my die is reducing the case at that point by .004". I think this means I took it where you expected it to be taken. My apologies for bad terminology.

 

[BoydAllen]

Don't apologize. You write a very good post. I sent you a PM.

 

[1S2K]

I'm getting closer to getting all this hashed out. Again, your comments are appreciated...to everyone. Could I raise again the issue of the SMK in the Fed GMM being seated to what is apparently a slight jam? The OAL of the cartridge is still under SAAMI but the head to ogive length is greater in this factory loading than my comparator shows with the same bullet just touching the lands. There is a slight "circle" on the bullet in an extracted unfired round in the Fed ammo. So, yes, it is in the lands a bit more than where I stopped when trying to determine the correct seating depth for reloads.

 

[BoydAllen]

If it shoots good, and does not have pressure issues, leave it alone and enjoy.