Short / long range BR neck clearance?

[rebs]

No. Neck tension is determined by the amount of tension applied to the bullet by the case neck. Neck clearance is the amount of space between the case neck and the chamber neck.Two entirely different items.

thank you for the information

 

[JFrank]

I have a barrel that isn't shooting as consistently as I would expect from the things I've tried up to this point. I'm starting to consider potential issues outside of powder, seating and charge tuning.

One thing is neck clearance. This is currently running .002" clearance. With cases that are annealed every firing I'm getting very slight resistance when inserting a projectile in a fired case. The resistance is consistent on every case.

I understand that the rule of thumb is a projectile should be able to slide freely inside the neck. Question is to those that are at the pointy end of short range / long range BR, are you still using this generic rule of thumb, or are you working down into this territory and getting consistency with all other things being equal?

I have heard of guys using very little clearance but to me that is pretty slim when you put things into perspective, a human hair is a thin as .002 and then factor in carbon and whatever grime gets picked up and deposited from bolt lube and dust in the air, nothing good happens after that.
I run .265 loaded round in a .268 neck and clean after each days shooting and haven’t seen any problems yet.
Knock on wood .

Jim

 

[gpoldblue]

I have heard of guys using very little clearance but to me that is pretty slim when you put things into perspective, a human hair is a thin as .002 and then factor in carbon and whatever grime gets picked up and deposited from bolt lube and dust in the air, nothing good happens after that.
I run .265 loaded round in a .268 neck and clean after each days shooting and have seen any problems yet.
Knock on wood .

Jim

I use .268 NK w/ loaded round of .2665" for .0015" TOTAL nk clearance...no problems whatsoever,but I rarely shoot more than about 17-18 rounds w/out cleaning. The great Hall of Fame shooter Ed Watson,in his own account in Precision Shooting magazine,said he used .001" TOTAL nk clearance and he won a LOT of competition. I figured if it was good enough for Ed Watson,it'd be more than good enough for me. It has proved to be beneficial in more ways than one.
Good luck and stay safe.

 

[JFrank]

I use .268 NK w/ loaded round of .2665" for .0015" TOTAL nk clearance...no problems whatsoever,but I rarely shoot more than about 17-18 rounds w/out cleaning. The great Hall of Fame shooter Ed Watson,in his own account in Precision Shooting magazine,said he used .001" TOTAL nk clearance and he won a LOT of competition. I figured if it was good enough for Ed Watson,it'd be more than good enough for me. It has proved to be beneficial in more ways than one.
Good luck and stay safe.

I just shared a perspective, I wasn’t telling anyone what to do.


Jim

 

[gpoldblue]

I just shared a perspective, I wasn’t telling anyone what to do.


Jim

I'm not telling anyone what to do either,just sharing a perpesctive also and letting anyone who's interested
know that the concept has been used with success all the way to the Hall of Fame.
This is America......people can shoot pretty much what they want to.
I appreciate your input..........thank you.

 

[Ccrider]

Cal-6.5x47
Barrel - Bartline 1.25" parallel 30" 1-8
Chamber- .293 neck
Loaded round - .291 measured with mitutoyo digital micrometer
Action - Bat M
Scope - NF Comp
Stock - PR&T F Open
Rest - SEB neo

The rest of the platform is proven with multiple other barrels and cals. I've shot 6.5x47 before BUT with a different reamer that had a bigger neck diameter and slightly longer throat. My ES is up in the 25fps range and my groups aren't consistent even at 200-300yds where ES doesn't have a huge impact. I've explored 4350 and varget which shows glimmers of hope then shoots 1moa elevation. I'm leading toward there being and issue with the chamber or maybe just unlucky with this barrel.

With es around 25, I wonder if you have some other problems going on.

What size are your groups and at what distance?

 

[Bill Norris]

I have heard of guys using very little clearance but to me that is pretty slim when you put things into perspective, a human hair is a thin as .002 and then factor in carbon and whatever grime gets picked up and deposited from bolt lube and dust in the air, nothing good happens after that.
I run .265 loaded round in a .268 neck and clean after each days shooting and haven’t seen any problems yet.
Knock on wood .

Jim

That's my numbers for my 6PPC as well. I believe accuracy can be found with each rifle and it will shoot it's best under totally different circumstances to some degree. Jack says there are different ways to go about getting the best accuracy from each rifle as well. It just makes sense to me that if there is any restrictions or possible restrictions in any area it could hinder accuracy. But to each their own.

 

[X Count]

Thanks for the info guys. I'm going to concentrate on neck clearance and case length for now as I know that's the thing which is different. As with all guns chasing a high level of accuracy it could be a dozen or more potential causes and they can be explored systematically.

 

[X Count]

That's my numbers for my 6PPC as well. I believe accuracy can be found with each rifle and it will shoot it's best under totally different circumstances to some degree. Jack says there are different ways to go about getting the best accuracy from each rifle as well. It just makes sense to me that if there is any restrictions or possible restrictions in any area it could hinder accuracy. But to each their own.

That is very true. If there was one blanket rule for every gun and barrel it would be too easy!