Bumping shoulders

hendrix's rifle

Well-Known Member
Can anyone advise the best way to bump shoulders back? I understand the principle of doing it however without spending money on various things from hornady what's the other options? Decided to give full length sizing a crack instead of neck sizing only, for no other reason than why not lol. Thanks
 
One way without a headspace gage is to size and try the unloaded case until it slips in and out like a wet eel . Just ajust the die down/up as needed, I don't use the expander ball to size the neck I use a mandrill to prevent pulling the neck back on withdrawal
 
One way without a headspace gage is to size and try the unloaded case until it slips in and out like a wet eel . Just ajust the die down/up as needed, I don't use the expander ball to size the neck I use a mandrill to prevent pulling the neck back on withdrawal
Seems to be fine after fire forming, no problems chambering hence the confusion?
 
I just adjust the die until the bolt just closes freely on a sized case. No extra tools. No extra dies. Works well. ~Muir
This is the problem, the bolt is free and closes fine before sizing? Im no whizz when it comes to loading but i can load, as i understood it and have seen it, the bolt os usually a little stiff. Not on this though lol. Thanks
 
It’s been long known in accuracy “circles” (F Class , Precision shooting competition etc) that Full length sizing is the most reliable way to resize brass to achieve consistent accuracy.

For that you need Full Length and (or) shoulder bump dies

You have to be really careful that you do not oversize the brass beyond safe tolerance and create undersized brass that effectively is a very loose fit in the chamber leading to dangerous issues during the firing cycle

The best method is to strip out the fire control mech (firing pin, and if possible ejector plunger) from your bolt and gradually resize the brass to allow the bolt to close with light fingertip pressure in your chamber - once that is achieved set your die lock ring to that setting and leave it alone

You may have heard people advocating measuring the base of the brass to see the amount of resizing the die is achieving - this should be used as a measure if and only if your brass is slightly sticky on extraction after setting the full length die

The only way to reduce the diameter of the case base is then to use a Small Base Body die to work the base / case body and NOT the shoulder

Following discussion on another forum this very same issue where someone was suggesting using a full length die to further reduce the brass diameter - if the die was in contact with the shoulder - to achieve a reduction of .001” diameter on for example, a 6.5/47 Lapua case the full length die would need to move .088” downwards which would move the shoulder to unusable and dangerous level


Good luck
 
This is the problem, the bolt is free and closes fine before sizing? Im no whizz when it comes to loading but i can load, as i understood it and have seen it, the bolt os usually a little stiff. Not on this though lol. Thanks

I am with Ronin on this. FL sizing is the way to go. I also agree with Paul O in that those expander balls are crap. When I get a new die, I take it out and throw it in the bin. Hate them. I size the brass and the neck and then post sizing, use an exander mandrel die with the relevant mandrel in to size the neck.

Anyhow, the comparators are something I quite like despite generally hating Hornady's array of various "measuring" devices like the COAL gauge and that rank stuff. Easier ways to do that in my opinion.

But for FL sizing, the bump insert comparators are quite useful, especially if you load the same cartridge for two different rifles and therefore do not want to leave the lock ring in situ on your die. It is just a comparator though. It is not taking a measurement that could be applied to another persons tool. It is purely giving you a reference point for your tool only so you can understand the different between the movement of brass on your cases.

You could do this with any machined piece of metal as long as it is square, fits flush on your caliper and will allow the case neck at some point to sit consistently in the machined recess so that you can take a "measurement/figure" from a blown out case and then by trial and error screwing your die in a little further (very small increments or you will oversize the brass) until you have bumped the shoulder back enough. I go 2 thou less than max chamber size to ensure ease of chambering without having any sort of excess headspace.

I keep a piece of blown out, fully fire formed brass for each rifle that shows signs of only just being able to chamber with a little bit of extra force on the bolt when closing. Bumping the shoulder back 2 thou on a piece of brass like that will ensure uniformity and ease of chambering in the field. Or if you do not have any brass that displays this behaviour, then take some measurements from a few pieces of brass from case head to a point on the shoulder and find the largest one and mark it up and size all future brass to that one.

I will check later when I get home but you might not really need the full comparator body. The bump insert on its own will suffice as long as you use it consistently. Obviously it is not attached to the caliper, so it is a bit of a faff but if you are barely using it, it will be fine and will provide a reference point from which to measure. They are only about a tenner I think from memory. The sinclair ones are better material I think than the Hornady ones and from memory are actually cheaper. I think they are deep enough so that the case neck does not protrude from the other side when the shoulder is resting on the recess. I will check later but I expect a tenner will see you good.
 
Agree with the above I full size only , the only one I bush neck size is the 6.5 CM for this I use a full length neck bushing die , all the other I use Redding standard Full dies .
but then I do have all the body /case measurement stuff lol.
 
Can anyone advise the best way to bump shoulders back? I understand the principle of doing it however without spending money on various things from hornady what's the other options? Decided to give full length sizing a crack instead of neck sizing only, for no other reason than why not lol. Thanks
For a modest fee, I can post you one of these things from Whidden -
Shoulder bump gauge
Regards
JCS
 
On options, don't forget neck-size + bump-only dies. (ie the die doesn't touch the case-body below the shoulder-line.) These used to be expensive custom jobs from outfits like Neil Jones, but Forster makes its 'Bushing Bump' sizer in a modest range of cartridges. They've never really caught on as far as I can see, but I'm a fan having used them in 223 Rem, 308 Win, 6.5X47L, and 284 all with excellent results.

All have been used in loading warm to hot loadings for 'minimum SAAMI' chambers and I've yet to need a full body-size on any case despite some getting up to around 10 firings. Chambering and extraction are as 'sweet' as with FL sized brass. It seems that the hard chambering / extraction encountered from neck-only sizing that is usually attributed to lower case-body expansion often comes from shoulders moving forward longitudinally creating a crush fit in the chamber rather than from radial expansion lower down. (This may not apply so much in 'slacker' factory chambers though - I've not used a bushing-bump type in loading for such a rifle - and a plain FL sizer may be better anyway for potentially marginally out of round or misaligned factory chambers.)

Bushing Bump Neck Dies - Forster Products

Issues over setting the die and measurement methods to get the right amount of 'bump' apply as per earlier posts - no difference with this type.

I'd never neck size only now for anything that is loaded to full normal or high-ish pressures. A single firing sees some case shoulders move enough to create noticeably harder chambering. (... and extraction too! If shoulder position makes final chambering hard, then primary extraction is equally affected - probably more so as the shoulder may have moved further in that firing.) What is also noticeable is that shoulder movement isn't necessarily consistent across all cases. I've been struck how much variance there is in a box of 50 common or garden type cartridges with 20-degree shoulders starting from new and neck-only sized for their second loading / firing. Just one firing at factory type pressures of around 58,000 psi sees maybe half chamber without resistance, quarter just produce a shade of resistance to final bolt closure, quarter have noticeably harder bolt closure. Crush case to chamber fit is known to affect pressures / bullet POI, so there is a potential effect on precision here. Neck only sizing often works very well though for modest pressure loads which apparently don't generate high enough pressures to move shoulders forward much or even at all.

Another alternative I use with some cartridges is two-stage sizing separating neck and shoulders/body jobs. A bushing neck-sizer such as Wilson types (or much easier and cheaper, the Lee Collet Die) is used then a Redding (or other make) body-only die. American and Canadian competition shooters, especially those loading 223 Rem for mid-range F/TR have taken to the LCD + body die process. Shame that Lee doesn't finish its collet dies as well as they once did - many have sizing tines as rough as the proverbial bear's rear end leaving deep grooves in the neck.
 
On options, don't forget neck-size + bump-only dies. (ie the die doesn't touch the case-body below the shoulder-line.) These used to be expensive custom jobs from outfits like Neil Jones, but Forster makes its 'Bushing Bump' sizer in a modest range of cartridges. They've never really caught on as far as I can see, but I'm a fan having used them in 223 Rem, 308 Win, 6.5X47L, and 284 all with excellent results.

All have been used in loading warm to hot loadings for 'minimum SAAMI' chambers and I've yet to need a full body-size on any case despite some getting up to around 10 firings. Chambering and extraction are as 'sweet' as with FL sized brass. It seems that the hard chambering / extraction encountered from neck-only sizing that is usually attributed to lower case-body expansion often comes from shoulders moving forward longitudinally creating a crush fit in the chamber rather than from radial expansion lower down. (This may not apply so much in 'slacker' factory chambers though - I've not used a bushing-bump type in loading for such a rifle - and a plain FL sizer may be better anyway for potentially marginally out of round or misaligned factory chambers.)

Bushing Bump Neck Dies - Forster Products

Issues over setting the die and measurement methods to get the right amount of 'bump' apply as per earlier posts - no difference with this type.

I'd never neck size only now for anything that is loaded to full normal or high-ish pressures. A single firing sees some case shoulders move enough to create noticeably harder chambering. (... and extraction too! If shoulder position makes final chambering hard, then primary extraction is equally affected - probably more so as the shoulder may have moved further in that firing.) What is also noticeable is that shoulder movement isn't necessarily consistent across all cases. I've been struck how much variance there is in a box of 50 common or garden type cartridges with 20-degree shoulders starting from new and neck-only sized for their second loading / firing. Just one firing at factory type pressures of around 58,000 psi sees maybe half chamber without resistance, quarter just produce a shade of resistance to final bolt closure, quarter have noticeably harder bolt closure. Crush case to chamber fit is known to affect pressures / bullet POI, so there is a potential effect on precision here. Neck only sizing often works very well though for modest pressure loads which apparently don't generate high enough pressures to move shoulders forward much or even at all.

Another alternative I use with some cartridges is two-stage sizing separating neck and shoulders/body jobs. A bushing neck-sizer such as Wilson types (or much easier and cheaper, the Lee Collet Die) is used then a Redding (or other make) body-only die. American and Canadian competition shooters, especially those loading 223 Rem for mid-range F/TR have taken to the LCD + body die process. Shame that Lee doesn't finish its collet dies as well as they once did - many have sizing tines as rough as the proverbial bear's rear end leaving deep grooves in the neck.

I use basic Lee dies for everything.

Full length die first, decapping/expanding rod removed so that it only touches the outside of the case. Add one or two layers of e.g 3M magic tape to the case head to create a shim. Gently gently gently adjust until it just snugs into the chamber with the sticky tape shims in place.

Now you have set the shoulder bump precisely. Lock that die down with a good locking ring or other thing, for repeatability, in your press.

Next take a Lee collet neck die and pass it through, no particular force applied. Pops out the primer too. The mandrel will expand the neck to correct size (given that the FL die was used without the rod inside).

For subsequent firings, just use the Lee collet neck die correctly, whilst also doing trial chamberings, maybe with sticky tape shim on the head, periodically, to determine whether another shoulder bump is required.

If so, start again with FL die, no rod, just to bump shoulder, followed by Lee collet neck die,

Observation: Yes some Lee collet dies can seem a little rough to begin with, but that all polishes out nicely, either with fine grit sandpaper, takes only a few minutes, or toss the bits into a tumbler.
 
Thanks for all the replys, I've had a whidden bump gauge from jambell :D @Laurie how the hell do you know so much?!


Lauries knowledge is extensive after a lifetime of shooting and submitting articles in the shooting press

Highly respected for his knowledge and a nice bloke too, had the pleasure of spending quite a bit of time with him one hot summer in New Mexico several years ago at the F Class World Championships
 
On options, don't forget neck-size + bump-only dies. etc etc etc

Laurie,

It is when I read posts like yours that I am reminded how little I know, how much I have to learn and how little time I have left to learn it!
I really wish there were a few more courses (standby for the anti-course brigade) nationally so a novice could sit and ask questions rather than lurch from one disaster to the next (which is my current method of reloading) alone in his man-cave.
 
If your cases chamber after resizing but not when loaded I would be looking at their overall length.
I had real issues with my .35 and my .303 until I trimmed them to the correct length.
 
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