Decapping and Neck Sizing Dies versus FL Dies

[NYDAN]

When I first started reloading in 1980 or 1981 I bought RCBS FL resizing dies and have used them ever since for all the calibers I have reloaded. I followed the instructions that came with the dies and collaborating instructions in the reloading manuals. I don't remember ever having any problems with them. Until recently I never used any tools to measure the head space dimensions on my fired or reloaded rounds. I now have RCBS precision mics for the calibers I reload.

I have determined that the chamber dia. of my .270 Win. is on the larger size (water capacity of 71 gr.). Since the headspace measurements run from +0.0005" for spent Nosler factory loads to 0.0000" for my spent reloads, the extra volume is coming from the diameter size, not the headspace dimension.

Through the years I have read Pro's and Con's concerning neck sizing only. I am considering neck sizing to "improve the fit of the reloaded cartridge to the chamber".

I seem to recall reading various discussions on that state that one of the advantages of using neck sizing dies is that they don't work the case diameter (longer case life). I also have read various discussions that stated that FL dies can be used to neck size if you have the measurement tools to set the dies so that you only bump the shoulder back to 0.001" under your fired round head space dimension. I am currently using this procedure with my new Norma brass. (the necks were slightly deformed and out of round and the headspace dimensions were running about (+0.0005 to +.001). I also seem to recall reading a discussion that stated that using FL resizing dies for neck resizing can introduce concentricity issues whereas neck sizing dies won't. That seems counter intuitive to me.

I reload to obtain the accuracy I want (moa or less), with the bullet I want, at the velocity I want, for hunting purposes. I do NOT compete and I do not shoot except for developing loads for hunting, and of course for hunting. So, I am not a high volume reloader.

My questions are:

1. What is the true advantage of using a neck sizing die if I don't care about case life? Would I gain anything by using a necking sizing die versus carefully setting my FL die to set back the shoulder to -.001" below fired dimensions?

2. What is the advantage of using a decapping die? They only seem to cost about $20.00 so the investment isn't great. But it adds another step. The catalog states that you can decap uncleaned and unlubricated brass. Is this enough of a reason (for me) to buy one?

 

[Sas874runner]

I have never neck sized. I know alot of people do though. The idea behind it is to have a case that fits exactly to the chamber. Another plus is not having to trim cases as much. Even though you neck size you still have to fl size after so many firings. The chambers of my rem 700's are all quite large and I still prefer to use a fl die set. As for case life I'm not sure it would change much especially if you are towards the high end of a powder charge. I reserve that I could be wrong on that though. As for a decapping die. That is all it does. No expander ball and no sizing of any kind. That's why lube is not needed. I do know a few people that have had to neck size in order to get good accuracy out of a certain rifle. Of the people I know they were all in belted cases. Hopefully what I could contribute was helpful. And I'm sure there will be others along to add to or correct anything I may be incorrect about considering I have not neck sized.

 

[DrMike]

The neck sizing die avoids overworking the brass, extending case life. The decapping die allows for cleaning, including the primer pocket. This is important to some people. I have a decapping die, and I use it occasionally. Usually, however, I clean the primer pockets after tumbling.

 

[PJGunner]

I use a decapping die to remove tumbling media from my primer pockets. A lot faster and easier that trying to pick that stuff out with a sharp object. :wink: :lol: 8) As far as neck sizing, I only have two sets od neck sizing dies, one for my 7x57 wich I don't use as it causes run out of the necks and refuses to cooperate when I try to fix the problem. The other is for my .375 &H Ruger #1H, Most of the time I shoot strictly cast bullets on that rifle so I neck size only for four reloads, anneal the necks and do a full lenght resize and start tthe process all over again. The load is not a hot one, just 49.0 gr. of 4895 and a 270 gr. RCBS cast bullet. (#37-250-FN) I've never even bothered to chronograph the load as it's for fun shooting and rapid reload practice. Accuracy from the bench is about 1.5" on average. So far, the 20 cartridges I have allocated for that particular load have been reloaded 20 times according to my notes. Necks are holding up just fine and the primer pockets are still quite tight. As the rifle is a single shot, I don't crimp the necks which helps keeping the necks in good shape.
Paul B.

 

[woods]

It depends upon what kind of neck sizing die you are talking about.

With a regular neck sizer with an expander ball there is no advantage IMO

With a bushing neck sizer you get 2 main advantages. One is that you get to set the bullet grip you want by buying a bushing that will give you that grip. Two is that you don't need any lube inside the neck

With a Lee Collet neck sizer you get many advantages. First is that you will get less runout and make straighter ammo. Also needs no lube inside the neck. You can also set your bullet grip by ordering smaller mandrels or sanding down the one that came with the die. The Lee Collet does less work hardening since there is sizing in only one direction, inward onto the mandrel.


A Universal Decapping Die is easy to set up and decap lots of cases fast. It also does not interfere with any "feel" you get when sizing.

YMMV

 

[tjen]

To under stand the differance and advantages read a reloading manual completely. Hornady's is a great manual as is Nosler & Speer. Hornady even has a video and I bet Speer or RCBS dose too.

A once fired case from your rifle thats neck sized will be the most accurate as you can get. Thats if every thing else is equil, the potenial for accuracy is there.

For all my big game hunting rifles I parcial size using a FL die with out bumping the shoulder. As long as the case chambers I am good. If a chamber is large there my be a little partial sizing of the upper body but there will be no head space.

For my small caliber CF's I use the Reddington Type S Match Neck Die set. And for just the 22 Hornet the LEE Collect Neck die set. The Hornet has a thin case and with the collect die I have yet to trim let alone split a case neck.

I clean my cases before sizing them, and the decapping pin pushs media through the flash hole cleaning it in the process. I clean the primer pocket with RCPS pocket cleaning tool on a hornady case prep assistant. So I do not size dirty cases and the sizing process clean out the flash hole. Inside of the necks get cleaned as well so its a win win win for me.

 

[rick smith]

Nydan, what you are doing is called partial FL sizing. You cannot neck size with a FL die since the body is in contact with the die before the neck enters the neck sizing area. The expander ball is the cause of runout problems with many dies. I prefer to use the Redding Type "S" neck sizing die without the expander ball. If I have to use an expander ball, I polish it to a mirror finish and use a dry lube. I neck size until the cases get snug to bolt closure and then bump the shoulder back 0.001-0.002", normally using a body die and then sizing the neck in a separate operation. That adds an extra step in the loading operation but results are better. I load thousands of rounds a year, normally at night so the time doesn't cut into any shooting or hunting.
I will test any new idea in my loading sequence, use it or omit it depending upon range results and how it affects the overall process.Rick.