Neck tension?

[nikonNUT]

@HARMON Ran another 30 thru her today. There are trigger control issues but I think I have the neck tension about right. First group was a cold, dirty bore....

Not sure what happened here...

Shooters lack of skill aside groups are MUCH better than what I was getting with the biggest bushing. Drop the ones where I shanked the shot and things are running right at or sub- .5 MOA.

 

[HARMON]

I would say that is extremely good from a factory rifle with over 1300 rounds of 338 Lapua through it!

 

[nikonNUT]

I would say that is extremely good from a factory rifle with over 1300 rounds of 338 Lapua through it!

Thank you, sir! I'm pretty pleased that she's playing nice(r) now.

 

[HARMON]

If you don't mind, where did you order your gage pin's from? I have a handfull of gage blocks that I use to verify my calipers and mic's, but the pin's would be more versatile.

 

[nikonNUT]

If you don't mind, where did you order your gage pin's from? I have a handfull of gage blocks that I use to verify my calipers and mic's, but the pin's would be more versatile.

Amazon, my friend. I picked up the Vermont Gage Class ZZ black oxide no go versions in .335", .336", and .337" for a whopping $11.85 shipped.

 

[HARMON]

Thanks much appreciated.

 

[accunlmtd]

You are doing a lot of good work, but I believe that you are missing one crucial piece of information. What is the measurement of the chamber neck. You really need to know where your chamber is on the standards; tight neck, loose neck, how much freeborn etc.
Strongly suggest that you either buy a pound of Cerrosafe and do a chamber cast ( very easy to do). Or, take your rifle to a gunsmith and have them do a cast. then you can really understand what is going on in there.

 

[Mhinagoya]

You are doing a lot of good work, but I believe that you are missing one crucial piece of information. What is the measurement of the chamber neck. You really need to know where your chamber is on the standards; tight neck, loose neck, how much freeborn etc.
Strongly suggest that you either buy a pound of Cerrosafe and do a chamber cast ( very easy to do). Or, take your rifle to a gunsmith and have them do a cast. then you can really understand what is going on in there.

THIS!

On average, my custom rifles shoot best with .004 - .006 neck to chamber clearance. I skim the necks of my cases to assure uniform case neck tension and proper chamber clearance, and anneal after every firing. Yes, I know it's gross overkill, but it works for me. I have also found that bullet runout and jump to lands has significantly more effect on accuracy than powder charge uniformity. I don't know why this is so. I wish I did.

I have one rifle that shoots best with an .020 jump to lands and another that shoots best with a .006 interference bullet to rifling. It makes no sense, other than proving that each rifle is an individual.

I am 'settling' for what I'm getting out of my .22-6mm as the barrel has a very limited lifespan and I won't be burning it up for the sake of load development. It is currently shooting in the .3 to .4 range. It should do better, but as I said, it is a 1,000 shot barrel, then it's gone. My Swift Ackley shoots ragged holes, but I cringe when I think about barrel life. I have a hawkeye borescope and I procrastinate when I should be looking at the bore. The old adage "Do not scope the barrel on a rifle that is shooting well" is true.

My customs were trued and barreled by Benchmark Barrels (30 minute drive from my home). They ain't cheap, but most top-shelf stuff isn't.

Word to the wise: Never tell your wife that you just built a rifle that burns the barrel up so fast that just the barrel costs $1 per shot.

Bill.

 

[accunlmtd]

THIS!

On average, my custom rifles shoot best with .004 - .006 neck to chamber clearance. I skim the necks of my cases to assure uniform case neck tension and proper chamber clearance, and anneal after every firing. Yes, I know it's gross overkill, but it works for me. I have also found that bullet runout and jump to lands has significantly more effect on accuracy than powder charge uniformity. I don't know why this is so. I wish I did.

I have one rifle that shoots best with an .020 jump to lands and another that shoots best with a .006 interference bullet to rifling. It makes no sense, other than proving that each rifle is an individual.

I am 'settling' for what I'm getting out of my .22-6mm as the barrel has a very limited lifespan and I won't be burning it up for the sake of load development. It is currently shooting in the .3 to .4 range. It should do better, but as I said, it is a 1,000 shot barrel, then it's gone. My Swift Ackley shoots ragged holes, but I cringe when I think about barrel life. I have a hawkeye borescope and I procrastinate when I should be looking at the bore. The old adage "Do not scope the barrel on a rifle that is shooting well" is true.

My customs were trued and barreled by Benchmark Barrels (30 minute drive from my home). They ain't cheap, but most top-shelf stuff isn't.

Word to the wise: Never tell your wife that you just built a rifle that burns the barrel up so fast that just the barrel costs $1 per shot.

Bill.

Been there, done that.... try a 6mm Ackley Imp. that guy will run thru throats pretty quickly. Luckily, I have a gunsmith who will do barrel set backs and rechambers for minimal cost. (bought my own reamer, so it is always the same).

 

[nikonNUT]

Well I went back out and shot what I had left of the .363" bushing ammo. Saw several sub-.5 MOA groups and that makes me happy! Weren't cloverleafs, more like peapods but still. Going to whip up a few with a .361" bushing and see what happens. If it improves I'll stick with it. If it doesn't or there are insignificant gains I'll go back to the .363". No reason to work the brass harder for .050" group improvement! At least in my mind. It's one 1" at 2000 yards so...

 

[HARMON]

Well I went back out and shot what I had left of the .363" bushing ammo. Saw several sub-.5 MOA groups and that makes me happy! Weren't cloverleafs, more like peapods but still. Going to whip up a few with a .361" bushing and see what happens. If it improves I'll stick with it. If it doesn't or there are insignificant gains I'll go back to the .363". No reason to work the brass harder for .050" group improvement! At least in my mind. It's one 1" at 2000 yards so...

That is really very good with the amount of rounds that have been sent down range.

Is the re-barrel project moving forward? If so you may consider having your case comparator bushing reamed at the same time to match the chamber.

 

[nikonNUT]

That is really very good with the amount of rounds that have been sent down range.

Is the re-barrel project moving forward? If so you may consider having your case comparator bushing reamed at the same time to match the chamber.

It is. Mark is currently covered up with the competition crowd getting new barrels for their PRS, NRL, and F-Class rigs. My plan is to limp the factory barrel along until May or June (when it's hot enough that all I want to do is lie face down on an A/C vent) and then get it to him to spin up 2 barrels for me. I will have him install one and I'll have a spare that I can always install and head space myself in a pinch! I will inquire about having a comparator insert made off his reamer. Thank you for the great idea!

 

[HARMON]

No problem, I'm looking forward to seeing the build.

 

[nikonNUT]

Well, I dropped ALL the way down on the bushing size and using the same .336 carbide mandrel (Dang that's snug!) I got the case neck where a .335 no-go kinda sorta wants to start and a .334 no-go slips in and falls slowly with the primer pocket plugged. I'm calling it .334" so .004" of neck tension. I'll load up 5 foulers (I always, ALWAYS, have a few cases that trim short), 10 for groups, and 5 to shoot across the magneto speed and see what happens.

 

[nortac]

@nikonNUT, perhaps you mentioned it before, but what do you use to trim your brass? My Wilson with its micrometer adjustment is very precise but slow.

 

[nikonNUT]

Right now I am using a Lyman brass Smith power trimmer. I like the concept as it indexes ioff the shoulder of a formed the sized case but the adjustments suck! And by that I mean once you get it where you want it set there’s no way to lock it down or retain that setting so the micrometer head can wander and if you’re not paying attention all the sudden you’re trimming short…

 

[HARMON]

I'm still using my old manual rcbs trim pro. I did install the trim pro 2 universal shell holder though.

 

[Ad Astra]

Let the record state: there's reloading, and then there's reloading.

AA

 

[Whisky]

Let the record state: there's reloading, and then there's reloading.

AA

Tell me about it. I just traded a guy an old Glock 22 that I never shoot for a Rem 700 in 338RUM and 200rnds of ammo. It doesn’t have glass on it and I’ll need to shoot up the factory ammo before I start reloading for it but I think I’ll be coming back to reread this thread and a few others.

 

[nikonNUT]

Attempt #3 at neck tension. Full disclosure, I had a heck of a time getting comfortable behind the rifle today but I shot my 5 foulers, and made my attempt. First 3 shots were amazing!

But wait! It gets worse.

What do they say? 3 shots shows the rifles potential, 5 shots shows the shooters potential? I'll buy that <sigh> I really need to work on my press (I tend to get antsy when the trigger doesn't break when I expect it to) but it looks like my breathing is under control. I think the .361 bushing paired with the .336" carbide madrel is as good as it's gonna get. ES and SD were about the same at 20 and 8.6 so until the Autotrickler V3 shows up I think I'm there. Next week I will try again from prone as my NPA off a bench is really, really bad and I figit ALOT reacquiring the target. Oh and I did a round count on the rifle and I'm at 1600 rounds down the pipe. 300 S&B factory rounds and 1300 primers gone so...