Shoulder Bump vs Bolt Closing Force

[otisrush]

New calibers and new tools....the questions....they are a flyin'....

I picked up a headspace gauge last night - along with a set of .243 FL dies.

I proceeded to set up my sizing die tonight. When I seemed to have it set to bump the shoulder back about .002" (that was my goal), when I put the sized case in the rifle, I would describe the bolt handle as being "stiff" as I closed it. I didn't have to push it forward extra hard - it was only the rotational movement of closing the bolt that seemed stiff.

So my question: Is that normal when moving the shoulder .002" or so? Or should the rounds "go in like butter" - like factory ammo does? If the bolt is stiff is that an indicator I should move the shoulder back even more?

It's a new Rem 700 - if that makes a difference. It only has 20 rounds through it.

Thanks.

OR

 

[Nevada Ed]

If a loaded round it could be the style of bullet and or the OAL
causing the tight fit.

If just the case.......
I would vote for more sizing for the "just like butter" feel.

 

[Twoboxer]

Work with empty once-fired cases to find out what is causing the problem.

Does an identical once-fired case cause bolt stiffness?

Is the case too long after resizing?

Did you actually bump the shoulder 0.002" ? Does it need more than 0.002"?

Is the problem actually a bulge near the case head? (Painting the lower part of the case with a sharpie and chambering it can help find that.)

If not the above, is the problem a bulge in the neck caused by improper seating and/or crimping?

Note that minor bolt stiffness because the shoulder hasn't been pushed back far enough can work well. Closing the bolt can "finish" the resizing job. Problem is at that point there's no tolerance for error.

 

[rwsmith]

Case gauge.......

A case gauge can help analyze these problems, but it's still hard to see what's going on internally. I had a problem with .30-06 that ended up being the shoulders collapsing ever so slightly on bullet seating and the misshapen case would not chamber. If I had one of the flat gauges that checks the case from the SIDE, the problem would have been easier to analyze.

 

[Forrest r]

Sounds like you need to adjust your fl sizing die down another 1/4 turn.

 

[sunnyd]

Been through this many times. Take the firing pin and spring out of the bolt and set it aside. Then chamber your resized brass. If there is resistance when closing the bolt, then ajust the sizing die down .001 and chamber again. Repeat until you have the feel you want. For hunting rifles, I keep repeating until little or no resistance is felt when closing the bolt. After the bolt is closing like you want, then seat the bullet and chamber again. If the feel changes, then your bullet seating depth may need to be adjusted. I have found this to be a fool-proof method for me.

 

[Rule3]

For a bolt action rifle you really do not need to full size the brass.

Take your once fired (factory) (from your rifle) and that is the correct fit.

Just neck size them and you have the best fire formed brass for that individual rifle.

Neck sizing will make your brass last longer and you may only need to trim once and a while.

 

[2152hq]

Been through this many times. Take the firing pin and spring out of the bolt and set it aside. Then chamber your resized brass. If there is resistance when closing the bolt, then ajust the sizing die down .001 and chamber again. Repeat until you have the feel you want. For hunting rifles, I keep repeating until little or no resistance is felt when closing the bolt. After the bolt is closing like you want, then seat the bullet and chamber again. If the feel changes, then your bullet seating depth may need to be adjusted. I have found this to be a fool-proof method for me.

This ^^^

Note he is resizing but not seating the bullet in the first step. Then trying that sized but empty brass for chambering and feel,
I sometimes take it one extra step and size the brass but w/o the expander in the die. This leaves the neck undersized so it does not contact the chamber at all. You are only feeling the contact of the case shoulder as you close the bolt.
(Make sure the case base area is not oversize and giving you a false shoulder reading and feel when closing the bolt. You should be able to resize the base of the 243 in a 30-06 or similar FL die w/o touching the shoulder,,maybe even a 45acp die. You just want to get a case that chambers w/o anything interfering except the shoulder contacting the chamber shoulder.)

When that is satisfactory to you,,then introduce the expander and try the brass again. There shouldn't be any difference. But on occasion the draw of the expander can pull the shoulder forward ruining you perfect placement from step one.
Now you know what did it,,lube the case,,polish the expander to remove the pull and draw put on the brass during that process.
Try again. If it still pulls the shoulder out, you may want to go to an M die to expand which is just an expander that works by inserting it in the case instead of drawing it back out.

When you have that finalized,,seat your bullet UPSIDEDOWN and flush with the case mouth and once again chamber and see if all is well.
The bullet being totally inside the case and flush removes any doubt about interference from rifling or the bore throat but still expands the neck to full dia w/a bullet seated.

If you now are getting stiff bolt turn down,,the neck of the case has most likely expanded to too large a dia with the bullet being inserted.,,case neck brass too thick.
You have to either inside neck ream or outside turn the necks down a few .000 to allow for clearance in the chamber.
Trying another brand of brass can sometimes remove this problem as they can vary those couple .000" so you don't have to do any reaming/turning.

Hopefully and usually,,the problem is solved after step #.

 

[MichiganScott]

It's been my experience that often the primer will extrude from the pocket on the first shot because the shoulder is back at SAAMI minimum or even less. This causes an incorrect measurement of case head to datum line on the case.

The resizing die is set such that the reloader thinks he is bumping the shoulder back when they actually aren't touching it. The shoulder move forward when the case is sized giving the problem that the OP is experiencing. The solution has been well described by other posters.

 

[Nevada Ed]

+1 on post 9;

A flat primer on loaded ammo is a must...... for rifle ammo.

If it looks like the tower of Pizza, you need a little more adjustment or primer hole cleaning.
One thing I hate is a primer that is not seated enough.

As for bulging primers, I remove the primer on my cases before I start any measurements or changes or use new brass, that has been checked for length and neck roundness.

Even new factory cases can come ..... out of round or with a light dent.

Good loading.

 

[bigedp51]

For a bolt action rifle you really do not need to full size the brass.

Take your once fired (factory) (from your rifle) and that is the correct fit.

Just neck size them and you have the best fire formed brass for that individual rifle.

Neck sizing will make your brass last longer and you may only need to trim once and a while.

The late Jim Hull the dirrector of the Sierra Bullets Ballistics Test Laboratory stated all ammunition fired in the lab was full length resized. And he full length resized all of his ammunition used in competition.

Jim Hull had a humorous saying about full length resizing..........

"The cartridge should fit the chamber like a rat t u r d in a violin case"

Kevin Thomas who followed Mr. Hull at the Sierra's lab and went on to shoot for Team Lapua USA also full lengths resizes all his ammo. And Kevin Thomas has quoted Jim Hull's saying many times in forums.

And the .001 to .002 shoulder bump is for the purpose of having clearance between the bolt face and the rear of the case. This is because the case can warp after firing and sizing and the base of the case would not be 90 degrees to the axis of the bore. Meaning if the case was standing on its base the case would be leaning.

Therefore a neck sized only case can cause the bullet to tip and be out of alignment with the bore.

NECO CONCENTRICITY, WALL THICKNESS AND RUNOUT GAUGE

Also referred to as "The Case Gauge," this item is designed to measure:
1) The curved "banana" shape of the cartridge case;
2) The relative wall thickness variation of a cartridge case;
3) The cartridge case head out-of-squareness;
4) Individual Bullets - out-of-round "egg shape" and/or
curved "banana" shape (excepting very small bullets);
5) The seated bullet and cartridge runout of loaded rounds. The accuracy of any firearm is determined -- and limited -- by the quality of the ammunition shot in it. The effect of imperfections in ammunition is cumulative; each flaw adds to the influence of all others. Precision shooters spend much time and effort "uniforming" cartridge cases, using advanced techniques to eliminate variation. Yet until recently, one of the most important of these variations has not been susceptible to detection by any device readily available to marksmen.

Bottom line, a full length resized case has "wiggle room" for the bullet to be self aligning with the bore.

 

[bigedp51]

+1 on post 9;

A flat primer on loaded ammo is a must...... for rifle ammo.

Actually the primer should be recessed below the base of the case, and have a slight preload on the anvil. (slight primer crush) This makes sure the legs of the anvil are in full contact with the base of the primer pocket

Below the military requires the primer to be .008 below the surface.

From the Nosler manual below.

As primers are seated to the proper depth, the anvil is pressed slightly deeper into the cup, lightly compressing the primer pellet. This sensitizes or arms the primer so that it will be ignited by the blow of the firing pin. However, primers that are seated too deep are hazardous as the anvil may be pressed into the priming pellet too far making the primer dangerously sensitive. Ideally, primers should be seated approximately .005 below flush with the case head. At this depth, they are sufficiently deep to be safe and sensitized, but are not so deep as to be out of reach of the firing pin.

 

[bigedp51]

otisrush

Taking the 700 bolt apart without special tools can be a pain even using the shoe lace trick.

Measure a fired case with the primer removed with a Hornady case gauge. If you have older eyes a digital vernier caliper helps. After measuring the case set the die to bump the case shoulder back .001 to .002.

This is where having Redding competition shell holders are nice to have and adjusting the amount of shoulder bump. With these shell holders you just change the shell holder to change the amount of shoulder bump without adjusting the die.

 

[fredj338]

When i set up dies for a new rifle i like the bolt to just close with minimal effort. I woul push the shoulder back another 0.002", try again. If your chamber isnt perfectly cut, 0.002" isnt much wiggle room to compensate.

 

[otisrush]

I thought I'd follow up......

Tonight went much better than last night.

I decided to start with the approach of taking out the decapping rod / expander. I'd do a pre-sizing check in the chamber - confirming it took a bit of effort to close the bolt. Then I'd size it - and check it in the chamber again. It turned out Forrest r was right: I ended up turning the die down about another 1/4 turn and that did the trick.

I put the pin/expander back in, re-ran a few of the cases, and they all chambered/closed the same. So it sure doesn't seem like I'm getting any case lengthening from the expander ball.

Thanks a bunch! I trimmed them up and primed them. Nothing like shiny-like-new primed brass - just itching for some powder and a bullet!

OR

 

[Rule3]

Please do not make things more difficult than need be?

A bolt action (as mentioned) gets the best results from fire forming your brass and neck sizing only. Check the first chapters of your manuals.

You can then mess with the bullet seating depth to be just off the lands if need be.

 

[Mad_Charlie]

I get better accuracy in all of my rifles using bottle neck cases by full length resizing.
I would never neck size cases for a hunting or battle rifle.
I do set up my head clearance.

 

[otisrush]

Please do not make things more difficult than need be?

A bolt action (as mentioned) gets the best results from fire forming your brass and neck sizing only. Check the first chapters of your manuals.

You can then mess with the bullet seating depth to be just off the lands if need be.

While I understand that, my understanding also is that after about 3-4 firings doing neck sizing only that a shoulder bump needs to be done. I've read that the cases get harder and hard to chamber so a shoulder bump needs to be done.

If that's true, it sounds like those doing neck sizing need to also have FL dies.....and I didn't want that hassle.

Is this not the case?

OR

 

[Rule3]

While I understand that, my understanding also is that after about 3-4 firings doing neck sizing only that a shoulder bump needs to be done. I've read that the cases get harder and hard to chamber so a shoulder bump needs to be done.

If that's true, it sounds like those doing neck sizing need to also have FL dies.....and I didn't want that hassle.

Is this not the case?

OR

Yes, that is correct. Eventually you will need to full length size

But it is much less "hassle" to neck size. (no lube, little to no trimming)

So yes, you need a FL sizing die also

Could be 3, 4 or more times that you can get by with neck sizing only.

The advantage of neck sizing is the cases do not "grow" so trimming is reduced, brass last longer and it is "formed" to your specific rifle and is the best fit possible.

FL sized brass should fit any rifle of that caliber.

"Shoulder Bump" is a kind of a "buzz" word. It is really just adjusting the correct FL sizing of your die. Once you have the resizing die set correctly you are good to go.

The bump is simply adjusting the die to correctly fit the chamber of your rifle,

You can use a case gauge or just the chamber of the rifle,

It helps if you keep the brass separated for that one rifle only And keep it all the same batch/headstamp,

I keep my bolt action 223/556 Varmint rifle brass completely separate from the brass for a semi auto AR 15

Neck sizing only, is not recommended for semi autos as they chamber/extract differently and will stick the brass in the chamber eventually

 

[7P's]

Easiest method is outlined in post #6 and using this tool for removing the firing pin.

Kleinendorst Bolt Disassembly Tool Remington 700