AusVarmint

G'day guys,

I have looking to order my bushes for a forster die in the next few days, i have skimmed and loaded a Remington and size ADI case just waiting for my Lapua cases to arrive

I have measured from 7.32 to 7.35 and 7.40mm =/ 0.2881, 0.2593 and 0.29133

Do people thing a .288, .290 and .292 would be the go?

Regards Dan

Two to three thou under your chamber neck size seems to be a pretty popular size, my 20/222 is two under. I found the coated bushes are very easy to use, read no lube required, although they are a little more expensive than the plain steel ones. My chamber neck is .232 and I use bush .230.

In larger cals I would be running at least 4 thou clearance. For us target shooters having a tight neck in larger cals is often a cause of vertical. I now wont compete with any of my guns unless I have 3-4 thou clearance in the dasher, 4 thou in the 260 improved and 5 thou in the 7mm.

Best thing as I said in another post is to take the diameter of a fired neck and get a bushing that will give you 1-2 thou tension with a loaded round that is say 4 thou smaller than the fired neck diamter. That may mean you have to turn but in factory chambers you should be fine unless your necking down from a larger case- you may need to neck turn. But if you want to run quality brass, lapua does make 260 rem cases, its just hard to find at the moment. I would get ahold of your cases first and neck them down with normal FL dies rather than bushing dies.

Hmmm i thought the measure was take from a loaded case. Its a factory chamber so exact size is un-known

I have 100-200 Lapua cases on the way down to me, which are the cases run in that rifle, (BRT still have some in stock though if anyone is looking for some)

With all that being said, should i need to FL size them? I was looking to shift to a bushing die to inhance the loading for the rifle..

dan_351 wrote:Hmmm i thought the measure was take from a loaded case. Its a factory chamber so exact size is un-known

I have 100-200 Lapua cases on the way down to me, which are the cases run in that rifle, (BRT still have some in stock though if anyone is looking for some)

With all that being said, should i need to FL size them? I was looking to shift to a bushing die to inhance the loading for the rifle..

Yes your right , the poster is talking about choosing a suitable neck size bushing , not about neck turning clearance.
Measure the ,loaded neck diameter and subtract the following.
For single fed by hand for target work .001
For general hunting magazine feed small to medium cartridges .002
For Auto , slide action , bigger cals and magnums . .003 to .004
So say your loaded round neck diameter is approx. .294 ( you did mention skimming ) then just subtract one of the above that suits and that's the bushing size .

dan_351 wrote:G'day guys,

I have looking to order my bushes for a forster die in the next few days, i have skimmed and loaded a Remington and size ADI case just waiting for my Lapua cases to arrive

I have measured from 7.32 to 7.35 and 7.40mm =/ 0.2881, 0.2593 and 0.29133

Do people thing a .288, .290 and .292 would be the go?

Regards Dan

Might not be how everyone else would do it but I would do the following.
Neck size all the Lapua brass when it arrives, measure the size after sizing and turn them all to the minimum measurement.
Load one and check the neck diameter of the loaded round.
Bushing size will be about 4 thou less than this measurement.

If you have a fired case from your rifle measure the neck size of it. This will pretty much be the size of chamber neck in your rifle.
The clearance Brad was talking about is the difference between the loaded round and the fired case.
If this is less than 4-5 thou then you will need to turn the necks down further. If you have to take 2 thou extra off the necks then the bushing size will have to come down by the same amount to keep your neck tension.
Chances are in a factory rifle you will have more than the 4-5 thou clearance.

Hope I made it as clear as mud
If you don't want to turn necks then a collet die will do a similar job.

haha the mud is settling on the bottom and clearing up.

I have no issue with turning skimming etc, i actually bought the turner originally to mush 'muck around a little' and found myself turning up the necks of my 30-06 ex mil brass... with EXTREME results

Once the necks were cleaned up my loading and especially load dev become lots clearer.

Besides i really don't get the chance to get out and shoot that much at all.

I think i have 2 of the 3 same cases sorted (though i am struggling to measure in metric non electronic calipers and then convert)
and to cover off Brads neck firing clearance i think the hunting chamber has that covers as when neck sizing a fired case you can see a HUGE set in when running up in the die.

Thank you everyone for helping out and being patient and helpful i'm sure over the year this has been done time and time again

I personally dont use bushing dies for using in no turn chambers (factory rifles) To me they are an extra cost that really isnt needed. I have used lee collet dies for ages (I use them in long range target shooting too) and my 260 shoots very flat at 1000yds and neck tension and runout is awesomely consistent. But if your turning down cases then yes they are good to achieve proper chamber clearance and suitable neck tension. If you are using lapua 260 cases you wont need bushing dies but if you choose to run a bushing die from memory a loaded round with them measured 0.295" so you would be after a 0.293 bushing (sorry dont quote me but those numbers ring a bell upstairs) If your necking down 308 lapua cases you will more than likely have to neck turn to get a loaded round to chamber- even in a factory chamber.

True you do need to measure a loaded round and minus one or two thou for your bushing size but if your loaded rounds dont chamber because the neck of a loaded round is larger than the chamber itself you are in trouble. So are you if you only have 1 thou or no chamber clearance as your case neck wont be able to expand to release the bullet (big pressure spike!) I nearly popped a heap of 22BR rounds years ago and it had me stuffed until we measured the neck of the "no turn" reamer which we then found out that was a tight neck and we needed to neck turn. Im quite surprised the cases even held that pressure.

Thanks Brad. i measured the not turned fire case at 0.2945

This is a photo of the case partly neck sized so i think there is plenty of room for expansion



I figure with turn or skimming the necks it gives perfect uniformity it to size perfectly the whole way around

It does but in a hunting gun, its never going to guarantee you of shooting better groups. So you have fired a case and without sizing the neck, it measures 0.2945"? That is a tight neck! My 260 improved is a 0.298" neck and loaded rounds in lapua 260 cases are 0.295" which is the tightest I would consider running. My 308 lapua cases necked down measure 0.294" loaded after turning. I would be really wary of using lapua brass in your gun as its thicker than the cases you must already be using.

If your chamber is a factory one then you don't need to worry about neck to wall clearance as skimming the neck will make more clearance not less . If you are going to partial neck size then that works ok with skim neck turning but you then need a body die to size the body so you don't disturb the neck . You can partial neck size with a Lee collet die by placing a machined washer over the case , to sit on the shell holder . This reduces the amount the case goes into the die .
A fired case will spring back from the chamber wall and be a smaller size than the chamber , .001 to .002 is common.
A standard 260 chamber neck is .298 to .299 ammo is around .295 to .297 so if a case came out .2945 it is not all that tight , .2945 +.002 spring back = .2967 . . 003 spring back is not unheard off .
If the chamber is tight in the neck it's only .001 to .002 .
I agree .293 to .294 loaded diameter should be ok as the actual chamber has to be a few thou bigger than that if a fired case came out at .2945 . Make up one dummy round to that neck diameter and see how it fits .

A bushing die has not one thing to do with neck clearance/chamber clearance so dont make that mistake.
Size a case,seat what ever projectile it is that you are going to use,accurately measure the OD in a couple of spots,then less 2thou and that should be good to go.
Now thats all fine and well as long as you dont change brands of brass,I used Remington brass in my 6.5 and the bush I use for the Lapua wont hold a projectile as the Rem brass is thinner in the necks...............just sayin.

Regards Chris.