full length resize or neck size only ?

[Dusty Stevens]

Your cases are not fully formed yet. Dont bump them until you feel the slight crush on a stripped bolt then bump them .002 short of that one. Some bump and some dont at this point

 

[BartsBullets]

I’ve done both and I shoot competitive Benchrest. I full length resize every time.

All I have say is listen to Boyd!!!


Bart

 

[SGK]

Your cases are not fully formed yet. Dont bump them until you feel the slight crush on a stripped bolt then bump them .002 short of that one. Some bump and some dont at this point

That's why I have just been bumping the long ones only very slightly. However, my point is I don't see anything close to 1-2 thou of case growth per firing. So even once fully fire formed I'd expect a bump of 1-2 thou not to return on firing. Maybe the lengthening upon firing increases as the cases form?

 

[Al Lu]

I always full size and in my quest to get a full size die (6mm BR)I was advise to call Harrells to get a full size die? The gentleman at Harrells tells me to send him a set of three time fired brass case neck size only .
Can you understand the confusions this can create? What came first chicken or the egg...

 

[cw308]

How are you doing your CBTShoulder method , is it on the bolt closing or bolt lift ? Starting with a clean fired case no primer . And if possible a stripped bolt using only the housing .

 

[Kracken McGraw]

Just for a comparison, I just formed new Lapua Brass from 6.5 to 6x47L on Forster FL dies. Shot these first time with 107SMK at slight touch. Shoulder moved out consistently.003”three thousandths”.

 

[Richard Coody]

I always full size and in my quest to get a full size die (6mm BR)I was advise to call Harrells to get a full size die? The gentleman at Harrells tells me to send him a set of three time fired brass case neck size only .
Can you understand the confusions this can create? What came first chicken or the egg...

Lots of reloaders have no idea what a fully fireformed case is. They take a piece of once fired brass and set up a shoulder bump. As long as a piece of fired brass chambers easily it is not fully fireformed and your die should be set to only size the neck. It is easy to do with a full length die. Just back the die off and size a piece of fired brass. First cycle you may not even touch the neck but by turning the die in a little and cycling the press you will see when you start to size the neck. Once the majority of the neck is sized and you haven't touched the shoulder you have the die set to neck size the rest of your cases. Load them, shoot them and cycle a piece of the fired brass. Repeat until a piece of fired brass chambers tight. That is fully fireformed brass. Usually at least 3 firings. Then you can set up your shoulder bump or send 3 pieces to harrells. Let them know it chambers tight.

 

[Dusty Stevens]

I always full size and in my quest to get a full size die (6mm BR)I was advise to call Harrells to get a full size die? The gentleman at Harrells tells me to send him a set of three time fired brass case neck size only .
Can you understand the confusions this can create? What came first chicken or the egg...

You can neck size with a fl die

 

[SGK]

How are you doing your CBTShoulder method , is it on the bolt closing or bolt lift ? Starting with a clean fired case no primer . And if possible a stripped bolt using only the housing .

I’m not sure if this was in relation to my post or not. Nonetheless...

In my case, given this rifle is a Blaser straight pull action, I can’t do all the stripped bolt sort of testing. I’m merely observing case growth after each firing. (I have some 3x fires RWS brass that has only ever been neck sized which I can check for comparison.) I’m only seeing very minor case growth between 1x fired and 2x fired. I bumped the few longer ones (it should have been just 9 of 50) just a smidgeon to align the batch a little better. I can back the die off a little and essentially just neck size them this next time to see what happens. I don’t get to feel bolt close or lift with this action in the same way with a conventional bolt action rifle.

(I hadn’t deprimed the 2x fired cases prior to measurement but can do so.)

 

[Al Lu]

Thank you Gents, as this is the first time I have been instructed on what a fully fireformed case is? And another reasons to make contributions to the Forum for the generosity of all the members.

 

[Toby Bradshaw]

I always full size and in my quest to get a full size die (6mm BR)I was advise to call Harrells to get a full size die? The gentleman at Harrells tells me to send him a set of three time fired brass case neck size only .
Can you understand the confusions this can create? What came first chicken or the egg...

You don't need a neck die to produce 3x fireformed brass. After each firing just decap, prime, add powder, drop a bullet in the unsized brass, and fire again. It doesn't matter that the bullet isn't held in the neck by tension.

 

[J F Johannes]

You don't need a neck die to produce 3x fireformed brass. After each firing just decap, prime, add powder, drop a bullet in the unsized brass, and fire again. It doesn't matter that the bullet isn't held in the neck by tension.

Please explain. This sounds a little dangerous to me. P.S. Not trying to start a fight, just would like to know the reasoning behind this.

Jim

 

[Uncle Ed]

Has anyone ever done a test on if the amount of shoulder bump effects accuracy?

With a full length resize case the case body is not contacting the chamber walls as German Salazar described in my post above. This means the only part of the case that contacts the chamber is the case shoulder. And the amount of shoulder bump and head clearance will help if the base of the case is tilted after the first firing. Meaning if the base of the case is tilted a little extra amount of shoulder bump/head clearance is to your benefit.

Below is Germán Salazar's responce to a question about partial full length resizing and saying a totally full length resized case has wiggle room for the bullet to be self aligning with the bore. Meaning the case body and base has no effect on bullet alignment and the cartridge should fit the chamber like a rat turd in a violin case.

The Rifleman's Journal
Germán A. Salazar

"a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway.

In conclusion, I believe that allowing the bullet to find a relatively stress-free alignment in the throat by full length sizing (including the neck) and turning necks to enhance concentricity gives the bullet the best probability of a well-aligned start into the rifling."

 

[J F Johannes]

If your not comfortable with Toby’s suggestion you could always use a cotton ball or TP in place of a projectile, then shoot them in the garage or back yard depends on the neighbors

I understand what your saying, you are containing the powder, no problem there, but a loose bullet could spill powder into action and chamber and cause bad things. My case necks when fired are loose. Just trying to understand this.

 

[Toby Bradshaw]

I understand what your saying, you are containing the powder, no problem there, but a loose bullet could spill powder into action and chamber and cause bad things. My case necks when fired are loose. Just trying to understand this.

Spilling powder isn't dangerous, just a nuisance. To keep from spilling powder just load the round with the muzzle pointed slightly upward. I've done this many times to produce fireformed brass for the Harrells and never had a problem.

The advantage of a bullet over a filler is that the bullet will push the case head against the boltface when firing (if you use a bullet that's long enough and the loading density is high enough to support the bullet heel).

 

[Bc'z]

Or just size the neck and continue with load development.

 

[SGK]

In conclusion, I believe that allowing the bullet to find a relatively stress-free alignment in the throat by full length sizing (including the neck) and turning necks to enhance concentricity gives the bullet the best probability of a well-aligned start into the rifling."

So we have a case which is freely floating in the chamber. Is a bullet sitting in the throat sitting true to the axis of the rifling? Or is it sitting butt end down nose up because the throat is bigger than bullet diameter? More so if bullet is being jumped? If the bullet doesn’t find alignment with the rifling until it has moved forward to contact them it seems hard to me that variances in case neck thickness to the extent less than the release dimension can have any affect on the alignment process. The neck has expanded out of the way in order for the alignment process to even begin.

 

[BoydAllen]

The problem is the "it seems to me" part. That can lead us astray, and keep us from doing experiments because we think that we do not need to because we already know what the outcome will be. Do the experiment. Believe your targets.

Let me give you an example. One of the best short range group benchrest shooters in the country is a long time friend. Years ago he wanted to know if cleaning the inside of case necks was better than not. He did the experiment and based on the outcome does not clean the inside of his case necks. His name appears in several places in the record books, and he is in the top ten of the Benchrest Hall of Fame. BTW all of his shooting is done with thrown charges. He holds and shoulders his rifle, uses a very simple rest, and squeezes a very soft rear bag. If someone that you knew was starting out in benchrest doing all of the things that I have mentioned, would you think that he was taking the wrong path? Many would.

 

[Bc'z]

So we have a case which is freely floating in the chamber. Is a bullet sitting in the throat sitting true to the axis of the rifling? Or is it sitting butt end down nose up because the throat is bigger than bullet diameter? More so if bullet is being jumped? If the bullet doesn’t find alignment with the rifling until it has moved forward to contact them it seems hard to me that variances in case neck thickness to the extent less than the release dimension can have any affect on the alignment process. The neck has expanded out of the way in order for the alignment process to even begin.

When I neck size my brass I try to leave the portion of neck next to shoulder junction un touched. " My belief " is that it aids in alignment.

 

[Dusty Stevens]

The problem is the "it seems to me" part. That can lead us astray, and keep us from doing experiments because we think that we do not need to because we already know what the outcome will be. Do the experiment. Believe your targets.

Let me give you an example. One of the best short range group benchrest shooters in the country is a long time friend. Years ago he wanted to know if cleaning the inside of case necks was better than not. He did the experiment and based on the outcome does not clean the inside of his case necks. His name appears in several places in the record books, and he is in the top ten of the Benchrest Hall of Fame. BTW all of his shooting is done with thrown charges. He holds and shoulders his rifle, uses a very simple rest, and squeezes a very soft rear bag. If someone that you knew was starting out in benchrest doing all of the things that I have mentioned, would you think that he was taking the wrong path? Many would.

Youd have quite a few here telling him hes doing it all wrong.