Brass Sizing and the Savage Barrel Nut Equation

[m12lrs]

Ok, so if the title of this thread caught your interest hopefully you have some good knowledge and understanding of proper brass sizing for precision ammo. This may get a little long winded, but I'll try to keep it simple.

BLUF: This is a research post not really an advice seeking post. I don't plan on changing anything. I know I could get a body die to bump the shoulder further or have the Shell holder or die shaved by a few thou etc. and I will use brass from this barrel as dummy rounds for Jim to do my barrels for next season. Just seeking others experiences with this or other methods of determining sizing specs etc.

4060

First off, my current barrel is a Cryo-Treated XCaliber, 8 Twist Chambered in 6.5x47 Lapua by Jim at Apache Gun Works. (Not a ploy) This has been the most accurate barrel I have had to date. There is no questioning the dope. Groups are always small and I have the reloading equipment to squeeze every ounce on performance out of it.

First My Process after every firing:

1. on my Lee Press: Deprime with Might Armory's "The Pua" die.
2. Dry Tumble in Walnut Media with Flitz and a dryer Sheet
3. Anneal on AMP Annealer with Prescribed Collet and Program
4. On my RCBS Summit Press: Size with Forster Bushing-Bump Die (.287 Bushing) (Will expand here later)
5. Tumble off sizing lube
6. Inspect and Clean Primer Pockets
7. Prime (I use my lee press for this as well)
8. Trim on Giraud Trimmer
9. Run all brass through a Sinclair .262 Carbide Mandrel Die
10. Charge to the Kernel on Auto-Trickler with Auto-Throw Combo
11. Seat on RCBS Summit Press with Forster Competition Seater die with the Stem honed to 140Hybrids.

Results:

Groups avg. .2-.4", SD 2 and ES 8 over 10 shot strings. Velocity 2780fps. Load is Lapua Brass (Obvious), CCI450, 36.6grs Varget (Within .02grs every charge), and 140 Berger Hybrid .035 off the lands.

Now the point of this post. My Forster Sizing die is maxed out. Can not bump the shoulder back any more than current. Obviously the goal is .002-.003 Shoulder bump measured with Calipers and Bump Gauge. Here's the scenario:

Using the Calipers and Bump Gauge I completed the Following measurements:

Go-Gauge: 1.425
No-Go: 1.428
Fired Brass: 1.429
Sized Brass: 1.427

Bolt close is slightly stiff, but not tight, so I know that brass is being worked very lightly. Again Sizing die is maxed out and will not bump the shoulder any further than the 1.427 measurement. Doesn't matter how tight it is... period. The beauty of the Savage barrel-nut and a prefit combo allows you to custom headspace for this all to work out which I took the time to do when setting the barrel up. However, I'd like to know if anyone else shooting 6.5x47 or other cartridges are getting numbers similar to this and are also bottomed out in their sizing die?

sounds like an excellent procedure.

the reason your cases are a little tight is not your shoulder bump. in fact i set my dies up for only a 1 thousandth shoulder bump.

the forster bushing bump die only sizes the neck and bumps the shoulder. it does not size the case body. i would reccomended you either get a body die or a full length bushing die or the forster full length sizing die honed to your neck specifications.

if you do decide to use a body die check your shoulder bump measurement afterwards. brass will probably grow and you will need to run it through your bump die again.

[Robinhood]

You lost me bro.... I’m running the RCBS Summit press for sizing....


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2 part answer.

I dont like having a tight cartridge fitting to any accurate rifle. That was popular a while back but these days I know of few people keeping the case fit tight in the chamber after loading. You already know someone that can help you remove material from both the holder or die. This is an answer to a question that may not have been asked.

Your RCBS press cams over when the ram reaches top dead center and then moves downward all in the same handle motion. This can be done with or without the die and the holder making contact. The Lee Classic has ram stops machined into the linkage. You can adjust your die to either make contact with the holder or not. One thing I noticed was that I get more consistent sizing with a shorter base to datum measurement while utilizing one of these 4 methods. Your method appears to be bottoming out on the die but it is not stated if you cam over. Camming over in my opinion if done with force when the die and holder contact, could increase the wear and tear on press. That is another discussion though. This post may be another discussion as well. My interest was which of the four you use. You use a press that has the capacity to cam over and you bottom out on the die. Where in the stroke this happens is still not clear to me.


Above M12lrs makes a great point.

[LoneWolf]

2 part answer.

I dont like having a tight cartridge fitting to any accurate rifle. That was popular a while back but these days I know of few people keeping the case fit tight in the chamber after loading. You already know someone that can help you remove material from both the holder or die. This is an answer to a question that may not have been asked.

Your RCBS press cams over when the ram reaches top dead center and then moves downward all in the same handle motion. This can be done with or without the die and the holder making contact. The Lee Classic has ram stops machined into the linkage. You can adjust your die to either make contact with the holder or not. One thing I noticed was that I get more consistent sizing with a shorter base to datum measurement while utilizing one of these 4 methods. Your method appears to be bottoming out on the die but it is not stated if you cam over. Camming over in my opinion if done with force when the die and holder contact, could increase the wear and tear on press. That is another discussion though. This post may be another discussion as well. My interest was which of the four you use. You use a press that has the capacity to cam over and you bottom out on the die. Where in the stroke this happens is still not clear to me.


Above M12lrs makes a great point.



https://youtu.be/vYJy-5rVs0s


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[Robinhood]

Your press cams over. What variation in length do you see with that press? (base to shoulder)

[LoneWolf]

Your press cams over. What variation in length do you see with that press? (base to shoulder)

Not seeing variation measurements are as explained in original post. I’m seeing limited capability of the sizing Die....


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[Brett]

I used a surface grinder but you can work'm down with course grit paper They don't have to be perfectly square as long as the maximum deck height at any point is .120 or less.

Gotcha, I thought you had a source for buying ones that were made with a reduced height.

[Texas10]

When I first headspaced my new 22-250 barrel, I apparently set it a bit too close. Although factory ammo would fit fine, my RCBS FL die would bottom out on the shell holder and not bump the shoulder back once my brass hit that stiff bolt closure max dimension. So after pondering my options, I loosened the barrel nut and backed the barrel off a few thou. Problem solved, everything fits and works like it should and I can get a good .0015 to .002 bump.

[Robinhood]

Not seeing variation measurements are as explained in original post. I’m seeing limited capability of the sizing Die....


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I see a barrel nut that compensates

[m12lrs]

sounds like an excellent procedure.

the reason your cases are a little tight is not your shoulder bump. in fact i set my dies up for only a 1 thousandth shoulder bump.

the forster bushing bump die only sizes the neck and bumps the shoulder. it does not size the case body. i would reccomended you either get a body die or a full length bushing die or the forster full length sizing die honed to your neck specifications.

if you do decide to use a body die check your shoulder bump measurement afterwards. brass will probably grow and you will need to run it through your bump die again.


you are getting a consistent 2 thousandth bump now which is more than i set my dies up for. why do you want a 3 thousandth bump?

if so just loosen the nut and back the barrel up a touch. the go gauge is minimum saami specs and the no go gauge is made to max saami spec. you could even headspace with the no go but i don't know why you would.

frankly i would set the die up for a 1 thousandth shoulder bump and resize the case body by one of the methods suggested above.

[LoneWolf]

So based on feedback I think I'm going to look into getting a honed FL die for next season. I don't plan on changing from the 6.5x47 for match use any time soon as it's literally been the most consistent and most accurate cartridge I've shot to date. So it would be an investment for down the road.

[Robinhood]

I think I'm going to look into getting a honed FL die for next season

Doing this changed my game in F/TR mid and long range. It was an experiment with a lee die that took me that direction about 7 years ago. The only die I have that can compete with it is a forester that I bored to the same dimensions.

[LoneWolf]

Doing this changed my game in F/TR mid and long range. It was an experiment with a lee die that took me that direction about 7 years ago. The only die I have that can compete with it is a forester that I bored to the same dimensions.

Just ordered one from Forster this morning! Really it only makes sense being that I now know all of the specs I want a sized case to meet!

[PaddyD]

I had a problem with not being able to set shoulders back on my .308 110FP. Rather than going through the trouble of tightening the head space on the rifle I just took .001" off the top of my shell holder. didn't need any tools other than some wet dry paper and an old piece of glass for a flat surface.