How much is too much when it comes to neck clearance?

[Dusty Stevens]

Lets say i have a case that when i skim turn and uniform the necks they measure .271 over a loaded round (after being sized with a .269 or .268 bushing)- is a .275nk too much having .002 per side? Ive shot this exact combo in this neck or a .278nk thousands of times with no issue just seeking others opinions.

 

[SHootSTraight22]

Lets say i have a case that when i skim turn and uniform the necks they measure .271 over a loaded round (after being sized with a .269 or .268 bushing)- is a .275nk too much having .002 per side? Ive shot this exact combo in this neck or a .278nk thousands of times with no issue just seeking others opinions.

I think .002 is recommended for most everyday/field/tactical use.. Mine just a hair tighter at .003 over a loaded round... Meaning .0015 pe side...

 

[ShootDots]

Personally, I like at least 3 thousandths clearance for most everything.. BUT with the 7MM's I like a MINIMUM of 4 thousandths clearance and 6 thousandths is not TOO much.

 

[ireload2]

I think the .008 to .010 found on many military rifles is way excessive.

Factory rifles are too large also.

I like .002 to .003 at the head and .002 at the neck.

The head cannot be easily adjusted. The neck can be turned if they are too tight.

I shoot a lot of cast bullets in which the case is a line to line fit with .0000 clearance.

I have shot jacketed bullets with .0005 clearance but you have to be very careful both in turning the necks and load development.
I do not recommend these super tight clearances unless you have the willingness to spend the time to make your ammo perfect.

 

[Alex Wheeler]

There is no too much when it comes to accuracy. The only negative to a lot of neck clearance is brass life.

 

[bblackwell]

The only issue I've ever had with too much clearance is the neck not sealing off properly.

 

[dmoran]

Dusty -

With 6Dashers and 243-AI I have tested clearances from 002 out to 008-thousandths and seen no accuracy gain or lose.
I personally like thin necks, for lighter squeeze, faster release, and consistent seating tension.
With that said, I run minimal of 003-thousandths clearance.
Some of my best Dasher match brass had 005-clearance and went +20-firings before retiring them to test brass.

My 2-Cents
Donovan

 

[Joe R]

ShootDots said:
Personally, I like at least 3 thousandths clearance for most everything.. BUT with the 7MM's I like a MINIMUM of 4 thousandths clearance and 6 thousandths in not TOO much.

dmoran said:

Dusty -

With 6Dashers and 243-AI I have tested clearances from 002 out to 008-thousandths and seen no accuracy gain or lose.
I personally like thin necks, for lighter squeeze, faster release, and consistent seating tension.
With that said, I run minimal of 003-thousandths clearance.
Some of my best Dasher match brass had 005-clearance and went +20-firings before I retiring them to test brass.

My 2-Cents
Donovan

I have learned more from the two guys above than all of my books (about 20) on shooting and reloading, personally I take their word as gospel.

Based on their advice, I've recently started thinning my 308 brass even more than I used to, so I have .009 clearance. My ESs (1-12)and SDs (1-5) have improved and become more consistent. I don't know if that is too much clearance but I will find out since I've started with a new barrel and 500 virgin Lapua cases. If I see any deleterious effects from the brass moving so much I'll get a new reamer and move to a tighter neck. Yes, I do anneal after each firing.

Joe

 

[BoydAllen]

As you probably know, there are reliable reports that top shooters have gone to larger clearances for their 6PPCs, something on the order of .003 total, and have reported better results at 200 for doing so. I was unaware that anyone was running more, but from your success, I would say that .004 has been proven workable.

I particularly liked dmoran's response because it is a report of the results of actual testing.

In the past, I have run as little as .001 (.0005 per side) on a 6PPC and .222 but that was undoubtedly because of the mistaken idea that less clearance would help accuracy. I think that I had a lot of company in this assumption, and that many may still be of that opinion.

Just two days ago, I was tuning a load and caught myself making excuses for why it was not shooting as well as I would have liked, but when I got it right, the results were markedly different. The simple truth is that sometimes it is hard to know what is causing a slight problem, and that we may guess incorrectly as to the cause. The only cure for this is to broaden the range of changes that we routinely try. The result of this can be new understanding of how things work, or why they do not.

Thanks for the information that you provided. I can see a test in the offing, using some of my brass that had been cut for a .262 neck chamber in a .263.

 

[dedogs]

This is turning into a good thread. Does anybody feel that less or more movement on the neck on firing has much affect on accuracy? Just trying to learn. dedogs

 

[dkhunt14]

I think you can get too little of clearance too allow the bullet to release cleanly. Especially if you get carbon in there. I tested like Donovan and saw no difference in accuracy at 1000. I usually run .003 total to be safe. Matt

 

[Joe R]

BarryB said:

The only issue I've ever had with too much clearance is the neck not sealing off properly.

Barry,
How much neck clearance did you have when the necks weren't sealing properly?

Joe

 

[BoydAllen]

Another issue that is related is that when necks have to be sized down a lot, bushing dies with floating bushings may not do their best work, as far as concentriciy goes. One way to get around this is to use a one piece die that has the desired neck ID. In my experience, this approach produces the best possible concentricity, better than a FL bushing die. Of course the matter of whether these differences in concentriciy show up on targets is another subject for discussion.

 

[bblackwell]

Joe ,

If I try to run more than .004 - .0045 neck clearance on my Dasher I get powder marks down the shoulder. Even when freshly annealed. It's not an accuracy issue , I just try an avoid a carbon build up in the chamber if possible.

 

[nhm16]

For my 7mm Walker, my reamer cuts a .315" neck, and I turn for a loaded round diameter of .3125", but my dies are from Whidden, so they are a very close match to the chamber and don't work the brass too much (which can cause brass flow and neck thickening).

 

[johara1]

There is no too much when it comes to accuracy. The only negative to a lot of neck clearance is brass life.

This is the issue, brass life, best find the spot where you have accuracy and brass life. 6 mm. clearance is different than 30 cal. or even 6.5. I've great luck with .001 per side on 6mm. in light gun but in heavy i found more heat and carbon needed a little more. I now use .0014but i did give up some life on the Dasher case……. jim

 

[Ccrider]

This is an old thread with some interesting observations from some knowledgeable people. Have any of you guys changed your thoughts on having too much clearance I’m a 6mm cartridge?

 

[Sniper338]

I'm no gunsmith expert, but I like 2 thou or alittle less. Just enough to get a clean release of the bullet, and not enough to stretch the brass alot. I dont like to work the brass more than need be. Longer brass life.

 

[338 dude]

Lets say i have a case that when i skim turn and uniform the necks they measure .271 over a loaded round (after being sized with a .269 or .268 bushing)- is a .275nk too much having .002 per side? Ive shot this exact combo in this neck or a .278nk thousands of times with no issue just seeking others opinions.

I think .004 is perfect .005 will work over five is too much

 

[Dusty Stevens]

This was for a customer’s information about 5 years ago. He got his info and didnt suffer any ill effects from running more clearance than i recommended. Brass lasted just as long and wore out the back end before the front end proving it doesnt matter as much as what youd read.