22-250 AI Resizing Confusion

[AccelR8]

I chambered my 22-250 improved so that the bolt barely closed on the Ackley improved go gauge. Then, when chambering new Winchester 22-250 brass, I wasn't feeling any of that .004” crush that I understand should exist so I tightened up the head space maybe a couple of thou until I got just a bit of resistance closing the bolt on the new, unfired 22-250 brass.

I fired twenty rounds. All went well there. Cases looked like they fully fire formed and accuracy was pretty good.

Here's where I'm confused. Full length resizing the fire formed cases with a Lee Ackley improved die, the die reduces the case bodies .004” in diameter uniformly all the way from the web to the shoulder. Case length increases about 009”. The shoulder moves FORWARD about .002” and the neck/shoulder junction moves forward about .001 on some cases and doesn't appear to move on others. Fired but unsized cases chamber easily. The bolt closes with no resistance. Full length resized cases there's a heavy feel closing the bolt. It'll close but it takes much more pressure.

Using my Hornady comparitor, as-fired cases measure 1.580 on the shoulder and resized cases measure 1.582. The shoulder moves forward.

I have several shell holders so I took .002 of the top of one. No difference, cases still come out at 1.582.

I took off another .002, and another...so far I've taken .008 of of the top surface of the shell holder and it's made no difference. The cases still come out at 1.582 and the heavy bolt closing is still there. The press ram is not running out of travel. I have the shell holder hard against the die .

What am I missing here? Could the Lee die be that far off? Shouldn't taking material off the top of the shell holder result in the shoulder being moved down? Is my chamber too short? If I cut it longer, increasing head space, I'll have too much for proper fire-forming, won't I? Or, perhaps I could jamb bullets to hold the case head against the bolt face?

By the way, I won't be able to come back here for 5 or 6 hours so any questions you want me to answer, Ill do so then.

 

[GLShooter]

Keep grinding the shell holder and turning the die in. It doesn't have to touch the bottom of the die. Spring Back for some of this is at work and you just need to shove the shoulders back further. I see this in some of my wildcats and will grind the snot out of the holder. We loaded 243 LBC using 6 PPC dies and the die is easily.0015 above the holder. Feeding and chambering is not effected.

Greg

 

[AccelR8]

Got home. Put the shell holder in the lathe and used the toolpost grinder to remove .002 at a time, trying it in the press resizing a fired case at each .002 increment and finally lapped the last ,001 to get resized cases with the should set back .002 with the shell holder against the die. Took off a total of .028 including what I ground yesterday.
.

 

[WVRJ]

That's a lot to have to peel off the shell holder.Does the bolt close tight on the Go gauge,or can you close it at all on the gauge?On the Ackleys I've worked on,I headspace them so the bolt will close smoothly on the Go gauge and I cut up a set of feeler gauges to use as shims on the headspace gauge.I like to make them so the bolt is pretty snug with a .001 shim and won't think about closing with a .003 shim.I fire form the brass with a light load of a fairly fast powder for the given cartridge.I seat the bullets for .015 jam to hold them against the bolt face.I use a smallish bushing in the sizing die to make the neck tension tighter than I would ordinarily run it.I haven't had any problems doing them like that,and I haven't had to use a machined shell holder.The way you did it will work,but too little headspace can cause problems with the bolt lugs and you'll need to make sure you keep the cases trimmed because you've taken some length away.Sounds possible that your sizing die may not be exactly right.

 

[boltfluter]

Your die is sizing the brass a little much on the body..002 would be better. But, the main problem is, your short chamber due to having short factory brass to start with. What you have now will work. On your next barrel cut the chamber to the go gauge and then create a false shoulder on your brass to set the headspace for the first firing. What you have now is a .22-250 short chambered by about .025 or so. Not really that big of a deal unless you sell the rifle. Hope that makes sense.

Thanks Paul

 

[SeabeeKen]

I do a number of ackleys and here is what I've found. Sounds as if you shortened headspace enough that your die cant properly size the case and bump the shoulder. When adjusting for a shoulder bump, as you are slowly turning down the die, the shoulder moves forward a couple thou because the body is being squeezed and the brass has to move and it moves forward, lengthening headspace. If you continue to turn the die in, you will eventually bump the shoulder. The lengthening means you are getting very close. This is normal. Id reset the headspace to the go gauge. neck up the brass to 24 or 25 cal, back off your sizing die and resize, working the die down in small increments until the case will barely chamber with a snug closure. Then just fireform and go from there.
By turning the barrel in to close on the case you created this situation.

 

[Plumsask]

I had my 6 AI chambered and headspace set to close with an interference fit on the brass being used. That being said, I did have to grind my shellholder down a few thousandth to allow shoulder bump.

 

[AccelR8]

I have read all the replies and understand what you all are saying. Makes perfect sense.

I had kind of suspected my chamber was too short because of my decision to match the chamber to the brass I had acquired, which is new Winchester.

This is my first Ackley Improved. I've done my fair share of cambering jobs but they've all been SAAMI spec, by-the-numbers, straightforward work. So I did as much research as I could on AI cartridges and the concepts involved. Of course one of the concepts that stood out was the importance of having the case head firmly against the bolt head during fire forming, and the method to accomplish this by having the standard cartridge head space on the neck/shoulder junction.

I read your replies this morning and concluded the “right” thing to do is cut the chamber a little bit more using the go gauge as a reference rather than the brass. Then, do the false shoulder thing as suggested. This had not occurred to me before. Then at lunch time, thinking about this again I remembered that supposedly one of the concepts was, one could simply shoot factory, SAAMI-standard, off- the-shelf ammo, expect reasonable accuracy and performance, and then end up with fire formed brass. This appeals to me very much I guess for obvious reasons.

I realize it's been many years since Mr. Ackley came up with this scheme and things may have changed, particularly with ammo manufacturers.. Factory ammo is made certainly to minimum SAAMI dimensions and maybe even a little smaller it seems to me. I wondered if I go ahead and reset my head space as above, will factory ammo I can buy be sized like the new brass I got. I would assume it would be and if so, the Ackley fire forming concept would be out the window, no?

I stopped at the two shops nearby on my way home today to try to get some factory rounds and look at them and compare, get some measurements. Well the 32.99 to 34.99 slots for 22-250 ammo were empty. I did find some Federal 22-250 but it turns out while I wanted to know, I didn't want to know 59.99 plus tax worth!

I normally have an overriding desire to do things “right” so I probably will increase my head space based on the go gauge and then figure a path forward from there. But I'm gonna let this all gestate for a few days before I decide. Try to get my hands on some factory ammo in the mean time.

Thanks all! I appreciate the advice. One question was asked, does it close on the go gauge? Not currently. It feels like I could force it but no, way too tight. And the point about keeping cases trimmed, that hadn't occurred to me. Thanks for that point.

Sorry for the long post!

 

[WVRJ]

I built a 223 a few years back and I set the headspace to be very snug on the Go gauge.I'm of the mindset that tight headspace is good for accuracy.But I took it a little too far.Factory ammo was at least an interference fit if not a crush fit.I knew I'd done too much of a good thing when I realized that the brass would have to be trimmed to a shorter than normal length because of how much I'd shortened the chamber.The action is a Remington 700 short action with the dreaded RR serial number prefix,which turned out to be a good thing because only one of the locking lugs was load bearing.I lapped the locking lugs more than I normally would to get a good contact pattern with both lugs giving 90% or better contact.After it was all over with,the headspace was right on.That rifle has a really good barrel and a well bedded stock and it's capable of quarter inch groups without too much stress.The best groups it's turned in at 100 yards are .211,.185 and .103 for 5 shots fired from a Seb Neo rest.It usually takes way less lapping to get good locking lug contact,but this one was not at all well made.Nowadays I use the shim on the Go gauge method and I'm pretty picky about having a nice snug headspace dimension but still be able to smoothly close the bolt on the Go gauge.Once you get to the point that the Go gauge won't fit,you have nothing to go by to tell what you've got.

 

[AccelR8]

Well, this evening I made an insert for my comparitor tool with a reamed .257” diameter hole. My chamber neck diameter is .257 so this gauge will contact the neck/shoulder junction where the camber does. So yeah, as someone said previously my chamber is .025 short. I bought box of Federal Premium 22-250 and those rounds measure 1.6595”to 1.6600” so, looking at SAAMI diagrams, the are about .004 or so less than the spec for the cartridge but pretty much on the nose for the chamber. So, after I get set up to proper dimensions I can use them for fire forming I guess. Only thing is I didn't realize they were nickel plated until I got them home.

 

[Dusty Stevens]

Ditch the lee die and grab a redding fl die or probably a whidden. I have been shooting a 22-250ai for many years on many barrels with no issue. And of course mine are chambered .004 short of the go gage like designed. Once you get it chambered there the regular off the shelf 22-250ai die works like butter. Your lee die is killing your brass

 

[AccelR8]

Yeah I don't think we need to be squeezing brass down .004.