Setting up sizing die - Wide range of BTS measurements on fired brass???

[MoneyWaster]

I recently had my .223 rechambered because it had excessive headspace resulting in case-head separation. Starting out on the new chamber I loaded up new Lapua brass and did a series of load ladders resulting in 100 once fired cases. I'm getting ready to set up my Redding Type S full length sizing die and want 0.001" shoulder set-back. Unfortunately, my once fired brass measures from the base to shoulder anywhere from 1.552" to 1.564". Most cases fall in the range between 1.554" and 1.556". What should my target be for shoulder setback? The average measurement is 1.556".

Why such a large range of measurements? Some loads were hot while others mild. Is that the cause? For what it's worth, the long fired cases will chamber in the rifle just fine without sizing. There is no resistance on the bolt while closing it and the cases will eject just fine.


Lou

 

[Comrade Terry]

For what it's worth, the long fired cases will chamber in the rifle just fine without sizing. There is no resistance on the bolt while closing it and the cases will eject just fine.

Why do you want to bump the shoulders? It doesn't seem to me to be necessary.

ETA: Look at this:

 

[T-shooter]

If they chamber ok without any extra force, there is no need to set back the shoulder in a bolt action, a semi auto may need a little to be reliable. The longest ones should be your setting point for the die.

 

[dkhunt14]

If your getting different measurements maybe your measuring system isn't up to snuff. Could be a bad caliper. I like to bump. 001 for matches and hunting. I would rather have gun function properly. Not upsetting the gun on bags and bolt opening and closing easy. Matt

 

[MoneyWaster]

I was of the impression that all cases need some amount of shoulder bump. I do have a neck sizing die that I can use also. Perhaps I'll just go with that.

 

[Mega]

Going on the variations in case length and the mention of a ladder test. I would say a lot of the cases have not been fully fire formed perhaps from the lighter loads. I wouldn't touch the cases until they are all showing the same length from a full load. In my view if you bump them at all you are back with a headspace issue with cases being way too short.

Don't know what you are using to measure base to shoulder datum point but my .223R Lapua fired cases measure 1.455" with a Hornady Headspace Gauge (insert A .330"). Not all gauges are the same so it really has no comparison to your gauge measurements. Point is my cases all measure the same and do not vary more than 0.0005". If I was to set up my die to bump then it would be less than 0.001" if possible.

 

[MoneyWaster]

Thank for the response Mega. I'm going to just neck size this round and see how they measure after the next firing.

 

[Mega]

I'm going to just neck size this round and see how they measure after the next firing.

Sounds like a wise plan.

BTW.. I very seldom use a FLS Die unless there is very good reason to and then if I want to bump shoulders I use a Body Die. Most all my hunting / varminting and target cases are reloaded using an Arbor Press and In-Line Bushing Die (Wilson). Maybe I'm a bit over the top but it's also a lot quicker for me.

 

[fguffey]

I recently had my .223 rechambered because it had excessive headspace resulting in case-head separation.

I am a reloader I am a case former also, when I have a chamber that is longer from the shoulder to the bolt face than my cases when measured from the shoulder to the case head I increase the length of the case from the shoulder to the case head. I understand that can be confusing to most but I off set the length of the chamber with the length of the case. For me? It is simple and easy because my case does not have head space and I measure the length of the chamber from the datum/shoulder to the bolt face. After I cut a chamber I measure and the form cases to fit, I determine clearance before I head to the range.

F. Guffye

 

[Bart B.]

Ideally, bottleneck cases headspacing on their shoulder will have between .001" to .003 head clearance to the bolt face when fired. Minimum for bolt guns, maximum for all others. They'll be that much shorter in case headspace from chamber headspace.

 

[spife7980]

I understand that can be confusing to most

No, it is confusing to ALL

 

[Rsadams]

Is it wrong to say if some loads were hot yet others mild maybe that could be why?? Just not hot enough to form the brass all the way out?? I would use the readings from the hot loads and set the die useing those measurements... Your probably not going to use the mild loads again...

 

[SheepDog]

I want to know how the guy in the video got that tight fitting case out of his gun after he fired it. That would be a very hot load well above safe pressures.

 

[Comrade Terry]

I want to know how the guy in the video got that tight fitting case out of his gun after he fired it.

Ask him. He's Alex Wheeler, and he is on the forum. Great guy - you'll enjoy him.

 

[fguffey]

New

Ideally, bottleneck cases headspacing on their shoulder will have between .001" to .003 head clearance to the bolt face when fired. Minimum foe bolt guns, maximum for all others. They'll be that much shorter in case headspace from chamber headspace.

Ideally and typically? And then there is the problem finding someone that can determine the difference in length between the chamber from the shoulder to the bolt face and the case from the shoulder to the case head. Many years ago I said I could measure the length of the chamber from the shoulder to the bolt face three different ways, reloaders and smiths recommend go type gages and I wonder how a reloader can measure the chamber length that is no-go gage length with a go-gage length gage. Shims? Shims are not included into my methods andf or techniques.

F. Guffey

 

[ttfreestyle]

Here we go again

 

[SheepDog]

fguffey,
Share! I only have two ways and neither will provide accuracy down to 1 thou (.001") much less 5 tenths (.0005").

 

[snert]

New brass. Not fully formed to chamber yet. If using in a bolt gun, wait till it starts getting hard to chamber then set up FL die to move it back (and since you are using a FL bushing die, it is basically a body die if you leave out the bushing, for those that mentioned using a body die.)

You can use Redding Competition shellholders to control the amount you push it back.

 

[GrocMax]

Are you by chance using CCI 41's or 450's, 7 1/2's, Tula SRM/5.56?

 

[Bart B.]

And then there is the problem finding someone that can determine the difference in length between the chamber from the shoulder to the bolt face and the case from the shoulder to the case head.

I and others have been doing that for decades.

Using fired cases from rifles with squared up bolt faces, full length size them to case headspace increments of .001" starting a couple thousandths inch less than a chamber GO headspace gauge to several thousandth longer. Use gan RCBS Precision Mic or Hornady LNL case headspace gauge to compare them to the steel GO gauge marking their size on them. Fill them with plastic steel epoxy to minimize (prevent?) shoulder setback when chambered.

Use them incrementaly starting with the shortest one gauging the chamber with rifle horizontal and a stripped bolt inserting one then let the weight of the bolt handle close the bolt. When the bolt closes only part way, chamber headspace is between that "gauge" marked length and the previous shorter one that let the bolt close easy.

Read through this again if not sure of what's happening. Ask for help if you choose.

Careful, F. Guffey; please don't confuse people wanting to learn how to do this.