Neck Measuements

[LAH]

First of all consider me ignorant of neck turning & such. I understand trimming necks but little else.

1. I have a Remington 721 in 257 Roberts Improved.

2. After firing the cases will not receive a bullet.

3. The fired cases will receive a .256” minus pin gage but nothing larger.

4. Sized cases [Winchester +P] easily receive a .254” minus pin gage but a .255” in a no-go.

5. My Redding expander ball measures just shy of .256”.

6. A loaded round case neck measure .287” at the mouth.

The barrel isn’t marked as to a Neck Size & I requested the barrel as a no-turn neck. Am I missing something here? You guys are the best so please take the above measurements & educate me. Thanks.

 

[243winxb]

Normal brass spring back after firing, will not let a bullet enter my 243 win brass, after firing 68 gr Bergers with IMR4350 . Starting & mid range loads. It takes a maximum loading to open the necks in my 2 factory chambered rifles.

A Standard fl die may oversize/work the necks to much, making it worse.
A Redding type S fl bushing die allows more adjustment when sizing necks.

 

[ShtrRdy]

Please tell us what the neck diameter of a fired case is.

 

[LAH]

Please tell us what the neck diameter of a fired case is.

I will a little later. I'm out for the day.

 

[LAH]

Please tell us what the neck diameter of a fired case is.

.288"

 

[47WillysGuy]

First of all consider me ignorant of neck turning & such. I understand trimming necks but little else.

1. I have a Remington 721 in 257 Roberts Improved.
( SAAMI standard diameter for the the chamber neck area is 0.2920")
2. After firing the cases will not receive a bullet.
( SAAMI Bullet specification is .258 minus 0.003" diameter.)
3. The fired cases will receive a .256” minus pin gage but nothing larger.
( Bullet diameter could fall between 0.255" to 0.258", very close to your pin gage diameter.)
4. Sized cases [Winchester +P] easily receive a .254” minus pin gage but a .255” in a no-go.
(So the smallest bullet diameter (0.255" is very close to your sized case internal diameter.)
5. My Redding expander ball measures just shy of .256”.
(The expander ball diameter is probably about right.)
6. A loaded round case neck measure .287” at the mouth.
(A loaded round should easily chamber, there should be 0.005" of diametrical clearance.)

The barrel isn’t marked as to a Neck Size & I requested the barrel as a no-turn neck. Am I missing something here? You guys are the best so please take the above measurements & educate me. Thanks.

Once you've processed your brass to accept primers, powder, and bullets, the neck internal diameter should less by 0.003 to .005(interference fit) of the bullet is a must.

 

[Preacher]

Have you checked the over all length, you may be pinching the end of the case...

 

[ShtrRdy]

.288"

That is cutting it close. The chamber neck diameter is probably about 0.289" which would give you 0.002" room.

It's not absolutely necessary that the bullet slip into a fired case. You'll have to decide if you want to turn the neck thickness down a little or monitor the loaded cartridge neck diameter.

 

[LAH]

Once you've processed your brass to accept primers, powder, and bullets, the neck internal diameter should less by 0.003 to .005(interference fit) of the bullet is a must.

The best I can measure the interference fit is .003”.

 

[47WillysGuy]

The best I can measure the interference fit is .003”.

Are loads chambering alright?
I commented previously, so here are comments which are easier to see and to read. Sorry!

1. I have a Remington 721 in 257 Roberts Improved.
( SAAMI standard diameter for the the chamber neck area is 0.2920")
2. After firing the cases will not receive a bullet.
( SAAMI Bullet specification is .258 minus 0.003" diameter.)
3. The fired cases will receive a .256” minus pin gage but nothing larger.
( Bullet diameter could fall between 0.255" to 0.258", very close to your pin gage diameter.)
4. Sized cases [Winchester +P] easily receive a .254” minus pin gage but a .255” in a no-go.
(So the smallest bullet diameter (0.255" is very close to your sized case internal diameter.)
5. My Redding expander ball measures just shy of .256”.
(The expander ball diameter is probably about right.)
6. A loaded round case neck measure .287” at the mouth.
(A loaded round should easily chamber, there should be 0.005" of diametrical clearance.)

 

[LAH]

Have you checked the over all length, you may be pinching the end of the case...

The fired, unsized cases are measuring 2.224 & 2.225. Hornady is showing max case length of .2.230. The fired cases chamber with no effort & dirty case mouths show no sign of touching.

 

[LAH]

Are loads chambering alright?

Are your loads off the shelf or do you hand load?

I load them. They were fire formed in this rifle. There is no resistance when chambering.

 

[47WillysGuy]

Are your powder loads light, medium, or “getting after it”. I figure brass isn’t fully formed until after a third firing. A light load maybe the cause minimal expansion. Good luck!

 

[LAH]

Are loads chambering alright?
I commented previously, so here are comments which are easier to see and to read. Sorry!

1. I have a Remington 721 in 257 Roberts Improved.
( SAAMI standard diameter for the the chamber neck area is 0.2920")
2. After firing the cases will not receive a bullet.
( SAAMI Bullet specification is .258 minus 0.003" diameter.)
3. The fired cases will receive a .256” minus pin gage but nothing larger.
( Bullet diameter could fall between 0.255" to 0.258", very close to your pin gage diameter.)
4. Sized cases [Winchester +P] easily receive a .254” minus pin gage but a .255” in a no-go.
(So the smallest bullet diameter (0.255" is very close to your sized case internal diameter.)
5. My Redding expander ball measures just shy of .256”.
(The expander ball diameter is probably about right.)
6. A loaded round case neck measure .287” at the mouth.
(A loaded round should easily chamber, there should be 0.005" of diametrical clearance.)

Thanks 47WillysGuy.
1. My loaded rounds should have .005 neck clearance if the chamber is cut to specs.
3. My Shars mic measures the Nolser 100 grain Ballistic Tips pretty much dead on .257 giving me .003 interference.
6. The rounds chamber with ease.
Maybe everything is fine & I'm over thinking this.

 

[LAH]

Are your powder loads light, medium, or “getting after it”. I figure brass isn’t fully formed until after a third firing. A light load maybe the cause minimal expansion. Good luck!

I'm using

Are your powder loads light, medium, or “getting after it”. I figure brass isn’t fully formed until after a third firing. A light load maybe the cause minimal expansion. Good luck!

The load was a 100 grain Nolser Ballistic Tip with 48 grains of IMR 4350 at 2.952 OAL. This is 2 grains under max according to Nolser online data.

 

[fkimble@charter.net]

There is another cause for not being able to slip a bullet in a fired case. When ejecting the case it will hit the inside of the action as the neck clears the back end of the camber with a good amount of force. This can/will slightly deform the end of the case neck. Try firing a case and slowly pulling the bolt back til you can get your finger on the case body to put pressure on it so it does not whack the inside of the action. You may need to practice a few times with a fired case before doing the actual firing. Support the case til it comes completely out and check the neck.

Frank

 

[SeabeeKen]

I think you are over thinking it. .015" neck thickness isnt horrible unless its a tight neck chamber.and is about the same as my 257AI as I recall. How many firings on the brass and has it ever been annealed? I've always found winchester brass a bit hard. Never had to trim a 257ai case yet. Doesnt sound like you have a problem

 

[LAH]

The brass was fired once to form it & the second time with these loads. And never annealed. Like you say I'm probably over thinking this.

 

[LAH]

As a side note, I have a 700 Remington in 30-06 & all fired cases accept a .308 bullet. [Just saying] Thank all you guys for taking the time to type your answers & thanks to all who took time for the PMs. I'm going to set up for neck turning & clean up the Robert's necks & see how that goes.

 

[mikecr]

People seem to naturally assume that where a little of something is good, a lot must be better.
This, eventually mutating to: if a lot is better, then it's required.
It's nonsense.