Full Length or Neck Only; What's Best Resizing for Accuracy?

[Dean2]

and worse "pills" for bullets

Better than Suppositories.

 

[Mram10us]

I don't understand the .002 thousandths neck clearance unless you are talking about each side of the neck and then I agree with you. Having first hand experiences with tight neck cartridges I found pressure if the loaded round had .003 (.0015 per side)or less clearance between the neck and the neck chamber. I consider the minimum to be .004 total and more if the necks are not turned, if the load is for dangerous game, it is recommended that dangerous game rifles have .008 total clearance.

I also agree that many would like to shoot below 1/4 MOA but when anyone wants to share how they do It, The non believers descend on them and state that It is impossible and that it's not worth the effort. I know people that are happy with one minute of deer and a pie plate at 100 yards is OK as long as you can hit it.

I will keep trying to make suggestions, and leave the convincing to others.

J E CUSTOM

here is one example. Cartridge is .344 neck. Chamber is .346. Thus, then.002" difference

the 300wsm example, is the same.
Am I missing something ?

 

[wbm]

Better than Suppositories

or tampons.

 

[Mram10us]

Where in these SAAMI cartridge documents is that specification stated?

https://saami.org/technical-information/cartridge-chamber-drawings/

With the cartridges I work with, it seems saami gives .002" clearance for the necks per the prints. I didn't check all in the saami book, so I'm sure there are some that are different

Can't believe I said "standardard". Meant standard.

 

[Bart B]

here is one example. Cartridge is .344 neck. Chamber is .346. Thus, then.002" difference

the 300wsm example, is the same.
Am I missing something ?

Yes, the tolerances. That matters to some of us.

Good points anyway.

 

[Bart B]

Don't wast your effort ........https://www.longrangehunting.com/threads/300-win-mag-headspace.208001/page-2

Why not? Tom Spotti wasted his time publishing this on Redding's website:

https://www.redding-reloading.com/tech-line-a-tips-faqs/145-dealing-with-headspace

Thousands believe likewise.

 

[J E Custom]

View attachment 168530
here is one example. Cartridge is .344 neck. Chamber is .346. Thus, then.002" difference
View attachment 168531
the 300wsm example, is the same.
Am I missing something ?

Ammo specs have a maximum and minimum dimension . So You cut a chamber to SAMMI specs, These dimensions are the standard for Ammo manufactures. They have Minimum and maximum Dimensions so they will chamber. Some ammo manufactures go with the minimum and others go with the maximum instead of the middle of the tolerance. This is why factory is so poor in many cases and so different batch to batch. As a builder I have to go with the SAMMI chamber dimension and let the loader adjust his ammo to suite him. Some want me to adjust the dimensions to suite there ammo but I cant take that liberty because if I/we did the same brand of ammo from a different batch could cause problems.

I have even seen factory ammo that would not fit a SAMMI chamber. Most of the time it is belted ammo and the belt wasn't machined to the correct dimensions. with shouldered cases even if it is to long as long as it is not to far out of spec. You can close the bolt on it. Also some military cartridge case are thicker and it is recommended that these necks are turned if you use them, unless you have a loose chamber that Is a SAMMI maximum. Chamber drawings are very useful to the re loader because he can decide if he wants everything tight (Close to minimum dimensions, or loose dimensions for semi auto's and easy feeding.

So keep in mind that the top drawing is for the AMMO and is for the ammo makers. The bottom drawing is for the reamer maker so That he cant go beyond these Dimensions and the smith and cannot confused or substituted one with the other.

The only time a reamer maker can deviate form the SAMMI dimensions is for wildcats (Anything that is not SAMMI specifications) and he has to mark the reamer with a different name or identify the change. The smith then has to mark the barrel with the name on the reamer so the owner cant wont get confused and place the wrong ammo in the weapon.

J E CUSTOM

 

[Mram10us]

Ammo specs have a maximum and minimum dimension . So You cut a chamber to SAMMI specs, These dimensions are the standard for Ammo manufactures. They have Minimum and maximum Dimensions so they will chamber. Some ammo manufactures go with the minimum and others go with the maximum instead of the middle of the tolerance. This is why factory is so poor in many cases and so different batch to batch. As a builder I have to go with the SAMMI chamber dimension and let the loader adjust his ammo to suite him. Some want me to adjust the dimensions to suite there ammo but I cant take that liberty because if I/we did the same brand of ammo from a different batch could cause problems.

I have even seen factory ammo that would not fit a SAMMI chamber. Most of the time it is belted ammo and the belt wasn't machined to the correct dimensions. with shouldered cases even if it is to long as long as it is not to far out of spec. You can close the bolt on it. Also some military cartridge case are thicker and it is recommended that these necks are turned if you use them, unless you have a loose chamber that Is a SAMMI maximum. Chamber drawings are very useful to the re loader because he can decide if he wants everything tight (Close to minimum dimensions, or loose dimensions for semi auto's and easy feeding.

So keep in mind that the top drawing is for the AMMO and is for the ammo makers. The bottom drawing is for the reamer maker so That he cant go beyond these Dimensions and the smith and cannot confused or substituted one with the other.

The only time a reamer maker can deviate form the SAMMI dimensions is for wildcats (Anything that is not SAMMI specifications) and he has to mark the reamer with a different name or identify the change. The smith then has to mark the barrel with the name on the reamer so the owner cant wont get confused and place the wrong ammo in the weapon.

J E CUSTOM

JE,
I understand they are saami, which is why I said and attached saami. Point is, there is generally a .002" difference between neck of cartridge and chamber neck specs. Don't anmo manufacturers use saami? Yes. Don't reamer manufacturers use saami, unless another print is used? Yes.

It's comical that you like to tell me exactly what I just said

 

[Tree Farmer]

I don't own, have the ability to shoot or the skill to load a rifle capable of 1/4 moa accuracy. But I sure want to hear from those who can. That's how I learn and what drives the sport. With any luck, maybe someday...

 

[okie man]

 

[Mram10us]

Where in these SAAMI cartridge documents is that specification stated?

https://saami.org/technical-information/cartridge-chamber-drawings/

Bart,
I appreciate you ask for proof. I have no problem citing references when asked. It throws up a red flag when a guy gets offended when you ask him to cite his sources, etc. I used the word standard based on what I've found when building saami spec stuff, but that might not be the best term since the 308 is different and probably others.

 

[denobravo]

bump the shoulder at least .001
Erik has his opinion

 

[Bart B]

Ammo specs have a maximum and minimum dimension . So You cut a chamber to SAMMI specs, These dimensions are the standard for Ammo manufactures. They have Minimum and maximum Dimensions so they will chamber. Some ammo manufactures go with the minimum and others go with the maximum instead of the middle of the tolerance. This is why factory is so poor in many cases and so different batch to batch. As a builder I have to go with the SAMMI chamber dimension and let the loader adjust his ammo to suite him. Some want me to adjust the dimensions to suite there ammo but I cant take that liberty because if I/we did the same brand of ammo from a different batch could cause problems.

I have even seen factory ammo that would not fit a SAMMI chamber. Most of the time it is belted ammo and the belt wasn't machined to the correct dimensions. with shouldered cases even if it is to long as long as it is not to far out of spec. You can close the bolt on it. Also some military cartridge case are thicker and it is recommended that these necks are turned if you use them, unless you have a loose chamber that Is a SAMMI maximum. Chamber drawings are very useful to the re loader because he can decide if he wants everything tight (Close to minimum dimensions, or loose dimensions for semi auto's and easy feeding.

So keep in mind that the top drawing is for the AMMO and is for the ammo makers. The bottom drawing is for the reamer maker so That he cant go beyond these Dimensions and the smith and cannot confused or substituted one with the other.

The only time a reamer maker can deviate form the SAMMI dimensions is for wildcats (Anything that is not SAMMI specifications) and he has to mark the reamer with a different name or identify the change. The smith then has to mark the barrel with the name on the reamer so the owner cant wont get confused and place the wrong ammo in the weapon.
J E CUSTOM

None of the USA Palma Team's rifles with custom 308 Winchester short chambers having less than SAAMI spec freebore had such data marked on their barrels.

 

[J E Custom]

JE,
I understand they are saami, which is why I said and attached saami. Point is, there is generally a .002" difference between neck of cartridge and chamber neck specs. Don't anmo manufacturers use saami? Yes. Don't reamer manufacturers use saami, unless another print is used? Yes.

It's comical that you like to tell me exactly what I just said

Again don't ask if you already know the answer.

You ask If you were missing something and all I did was try to help You.
It sounded like you didn't understand the different purposes of the two Specifications. It sounds more like you just want to argue.

I will leave you with it and, let you make the same mistakes that I did over the years.

Have fun

J E CUSTOM