Shoulder bump or neck size?

[62flint]

I bump the shoulder back .002. I found for my self and my rifles neck sizing only makes chambering /feeding harder. I like accuracy but I also like function. bumpig back a little is a compromise.

 

[AZDAVE]

For hunting rifles I use a .002 shoulder bump. in precision target rifles neck size.

 

[Hogpatrol]

I go with what the LR guys do. For consistency, full length every time with Redding neck bushing dies and competition shell holders. Change shell holders until correct fit of empty case to chamber. Don't use the buttons that come with the dies either.

 

[intj]

People are going to do and believe what they want. However, I doubt you can find any serious precision long range shooter that neck only sizes. Cortina covers the F-Class guys. The next and final step up in precision long range shooting is long range benchrest.

I don't know of any decent competitor in LRBR who neck only sizes. Understand that no one on the planet shoots smaller groups at 600 and 1000 yds than LRBR competitors. Everything we do is done with the goal of shoot as small of groups and aa high of scores as possible.

I personally have shot multiple 10-shot groups in competition at 1000 yds that are under 5". My best was under 3.9", and the record is in the 2.6" range. For 5-shot groups, 3" at 1000 yds is considered good, 2.5" is a screamer group, and the record is a little over 1".

in LRBR, we can't leave anything on the table if we want to shoot well. The load prep and load tuning we do is well beyond what most have even thought of. I promise if neck only sizing was an advantage that we would do it.

We typically bump shoulders around ,002-,003". We also run more neck clearance than we used to. A tight fitting case in the chamber is not your friend when it comes to accuracy.

 

[cash_tx]

As a slightly-past-amateur level reloader, I am constantly learning new things and I am fascinated with this thread. Can someone educate me a little more on the topic of bumping the shoulder back? Does the FL resizing do that by default; and if so, but how much on average? I've only lightly experimented with partial-length and neck sizing; most of what I've done has been full length.

Also, what is the proper way of measuring how much the shoulder has been set back?

 

[Houston Bill]

As a slightly-past-amateur level reloader, I am constantly learning new things and I am fascinated with this thread. Can someone educate me a little more on the topic of bumping the shoulder back? Does the FL resizing do that by default; and if so, but how much on average? I've only lightly experimented with partial-length and neck sizing; most of what I've done has been full length.

Also, what is the proper way of measuring how much the shoulder has been set back?

Great questions and I am interested in the answers as well.

 

[intj]

A full length sizing die can be setup to neck only size, bump the shoulder a given amount, or fully push the shoulder all the way back.

The best practice in almost all cases is to bump the shoulder .002 to .003. There are exceptions. The easy was is to get something like a Hornady headspace gauge and measure your fired case. There are other ways.

Next, starting with your die a turn or so from being able to contact the shell holder, size a case and measure it. Screw the die down a little more and resize and measure again. Keep doing that until you get the correct shoulder measurement.

That is the basic idea. There are many other things that can go into this process like bushings, expander mandrels, small base sizing, neck tension, etc.

For perspective, I neck turn, experiment with neck tension with bushings, make sure my die matches my reamer, and measure every case after sizing to ensure they are as identical as possible for my LRBR rifles.

For my 416 Rem I am taking to Africa to hunt buffalo in a couple months, I just run the cases through a non-bushing FL die and bump the shoulders .002 to .003".

My 416 can manage an inch 3-shot group at 100 yds. My LRBR rifles have shot one-inch 3-shot groups in testing at 1000 yds. The applications are different so the way I reload for each is different.

 

[Nevada Mike]

I guess I should mention that I load my belted cartridges trying to get close to headspacing on the shoulder. My DG rifle (404J) I full length resize and don't worry about brass life - I just want reliable feeding and BANG.

 

[khesser]

As a slightly-past-amateur level reloader, I am constantly learning new things and I am fascinated with this thread. Can someone educate me a little more on the topic of bumping the shoulder back? Does the FL resizing do that by default; and if so, but how much on average? I've only lightly experimented with partial-length and neck sizing; most of what I've done has been full length.

Also, what is the proper way of measuring how much the shoulder has been set back?

I’m gonna post some links that are worth watching. These video are coming from guys who compete at a high level in Precision Rifle Competitions or load more ammo in a year than most will shoot in a lifetime.

 

[Axle2010]

I’m gonna post some links that are worth watching. These video are coming from guys who compete at a high level in Precision Rifle Competitions or load more ammo in a year than most will shoot in a lifetime.

Great videos, thanks for posting!

 

[intj]

Anytime you see an RCBS Chargemaster anywhere near the words "precision" be wary.

PRS load techniques will work fine for hunting rifles. However, few of them do true precision reloading because the accuracy requirements of PRS aren't that demanding. It's the shooting positions, the time available, and the conditions that make PRS demanding.

If you want to know the deep details of true precision reloading--and if you do it will drive you nuts, look to what LRBR does. Weighing primers, seating primers to an exact crush, volume sorting brass, sorting bullets, maybe bullet pointing and trimming, measuring every case after sizing and every bullet after seating, tuning loads to .1 grains, tuning with neck tension, tuning seating to .001", finding a load for cycle one vs cycle two, keeping ammo at a constant temp in a cooler, finding a load for various temperatures, etc.

All that stuff matters in LRBR. It doesn't matter in most other disciplines. What does matter across all disciplines is to develop a consistent and thoughtful approach to load development and shooting.

 

[Nevada Mike]

"Anytime you see an RCBS Chargemaster anywhere near the words "precision" be wary."

Ha! I use an RCBS 505 (Ohaus) and an inexpensive E scale that I've found to be very accurate. Most of my riles will deliver sub MOA groups at 100 yards within a lot of the fuss and bother cited in the above posts and since I am not a competition shooter it's good enough for my purposes.

 

[intj]

"Anytime you see an RCBS Chargemaster anywhere near the words "precision" be wary."

Ha! I use an RCBS 505 (Ohaus) and an inexpensive E scale that I've found to be very accurate. Most of my riles will deliver sub MOA groups at 100 yards within a lot of the fuss and bother cited in the above posts and since I am not a competition shooter it's good enough for my purposes.

The 505 is accurate to about .1 grains and can be tuned to kernel accuracy, but the inexpensive e-scales are not very good.

Years ago I checked my RCBS 10-10 and my RCBS Chargemaster with my Sartotious Entris 128-1 scale. The Sartorious measures to .001 grains. IIRC, that's its accuracy level as well but I would have to verify. The 10-10 was good to .1, the Chargemaster was good to .3. That means when the 10-10 and the Chargemaster said a powder charger weight a certain amount, it was off by the error I listed.

For many cartridges that doesn't matter, for many it does. So while the cheap e-scales may be "good enough" for many applications, they are NOT precision.

 

[Nevada Mike]

No - not 'precision' but I can verify the numbers on my RCBS 505 to 1/10 grain. I doubt that this level of accuracy needs to be exceeded, given the host of other variables at play. So I am happy with my $50 Chinese scale, which is much faster in use than the 505 balance beam scale.

 

[intj]

I don't think you can use your 505 to truly verify your Chinese scale. You need a real lab balance for that.

The easy button for all of this is an Autotrickler V4 on an A&D FX-120i. It measures to .002 grains, which is about one kernel accuracy. It's also fairly fast. For my matches I have to load 150+ extremely precise rounds and the V4 and A&D are a big part of that.

If I hadn't had enough budget for the V4/A&D, I would have sent my RCBS 10-10 to Scott Parker to tune it. His scales are 1 kernel accurate, though being a manual scale they are slow. I think Scott like the 505 even better that the 10-10 for tuning.

 

[fourfive8]

For pure target shooting and maximum accuracy potential, custom collet neck sizing dies may yield the best results. For hunting ammo for any game, not just DG, I use and adjust full length sizing dies to both touch the shoulder and swage the body just enough to guarantee every round will load and extract without resistance.

 

[intj]

For pure target shooting and maximum accuracy potential, custom collet neck sizing dies may yield the best results.

It is counter intuitive for many, but pure target shooting and maximum accuracy is achieved with shoulders bumped .002" to .003". Maximum accuracy describes the very discipline I compete in, long range BR. Every serious competitor bumps the shoulder. We have been bumping shoulders for at least the last 20 years.

 

[Bob Nelson 35Whelen]

@

Some handloaders say you should bump the shoulder .002" - .004". Others say fireform, then neck size only. For non DG loads what do you like to do? Why?

@Nevada Mike
I always fireform my cases then just neck size until they get a bit hard to chamber. After that I full length size, trim, chamfer and anneal my cases and start the process again.
Do what works for you tho.
Bob

 

[Ontario Hunter]

@

@Nevada Mike
I always fireform my cases then just neck size until they get a bit hard to chamber. After that I full length size, trim, chamfer and anneal my cases and start the process again.
Do what works for you tho.
Bob

This makes sense.

One problem I have with bumping the shoulder on 404J is the shoulder is so gently sloped that it doesn't take much bump to negate snap over. The cartridges can be forced forward into the chamber rather than letting the extractor snap over the rim. And, for me anyway, snap over is important for a dangerous game rifle hunting buffalo. My standard Mauser only carries three in the magazine. Belted cartridges or those with sharp shoulders (e.g. Weatherby) won't have this issue. So I only neck size and carefully check each loaded round by test cycling. If at all tight when closing the bolt (and so far this has not been an issue), I will pull the bullet and full length resize. Never had a case stick in the chamber (except RWS cases that didn't snap over due to short case length and thick rims). Bob's routine is more thorough.

 

[Ontario Hunter]

Question: if I use my full length die to crimp, am I also bumping the shoulder?