30BR neck tension

[fm1947]

if you use a bushing what size are you useing, assuming your 30br has a .330 neck and of coarse they have been turned

 

[gunsandgunsmithing]

Most use 3-4 thou. neck tension. Can't say what bushing will give you that amount without knowing what your necks are turned to. For a .330 neck, most turn for a .328 loaded round so a .325 bushing should give .003 neck tension.

 

[fm1947]

thanks my necks are .328, and I use a .324 bushing I was wondering maybe if that might be to much, if I use a K&M expander I am at .328 so my thought was to try less neck tension so I ordered a .327 & .326, I turned then down to .011, I think I read Al Nyfus turned to .010 but i used this formula 330-308=22/2=11

 

[JCummings]

"I read Al Nyfus turned to .010 but i used this formula 330-308=22/2=11" equals 0.000 clearance between case and chamber throat ==> DANGEROUS!

 

[RGRobinett]

thanks my necks are .328, and I use a .324 bushing I was wondering maybe if that might be to much, if I use a K&M expander I am at .328 so my thought was to try less neck tension so I ordered a .327 & .326, I turned then down to .011, I think I read Al Nyfus turned to .010 but i used this formula 330-308=22/2=11

Though 'neck-tension', bushing size, seating depth are not, "carved in stone", most barrels will provide TOP performance using 0.002" of total neck-clearance (in this case, a .328" loaded-round neck diameter, as measured across the heel of the seated bullet) and sizing with a .324" bushing. Often, less 'neck-tension' makes for somewhat poor grouping . . . but, all barrels are not created equal, so, some experimenting may be in order . . .

"but i used this formula 330-308=22/2=11" - assuming that you are experiencing disappointing performance, this could be a large part of your "problem". With a bullet sans a pressure-ring (rare on a custom, hand-swaged bullet - most will have a 0.0003" to 0.0004" pressure-ring), you are set up for ZERO clearance between the case-neck and chamber: you have a force-fit; your actual loaded-round neck-diameter (with a custom bullet) is probably about .3304"! ???

Again, while not an absolute, neck clearance ranging from 0.0015" to about 0.003" has a proven performance record. If you own a 30BR chambered barrel (.330" neck diameter) which does not shoot acceptably small groups, using the 'default' .324" neck bushing, .328" loaded round [neck-diameter], and a 'jam-seat', you have an unusual barrel - not necessarily a bad one, just somewhat out of the norm: you'll have to "hunt-up" what your barrel 'wants' . . .

MORE neck-tension is usually a good thing, less, not so good . . . but, either way, it appears that you NEED some clearance - .011x2= .022"+.308"=.330" . . . with a 'custom bullet, thus pressure-ring, you are forcing the loaded round - remember, about .3304" - into the [.330"] chamber. Good shootin'! RG

 

[fm1947]

Thanks Randy I am useing your bullets, accuracy is good but I always try to improve or make sure I am doing right, I will call you later
My loaded round is .32845 , I think my problem is my gauges are just not so good CHEAP only one realy good one my mic.
Frank in Missouri

 

[AlNyhus]

I think I read Al Nyfus turned to .010 but i used this formula 330-308=22/2=11

Frank, I don't turn to a specific neck thickness, for the reasons Randy stated. I simply turn the necks to give whatever neck clearance I want (as measured over the p.r. of a seated bullet). Whatever the actual neck thickness is when I've turned them....that's what it is.

Randy's response is spot on and as close to The Gospel as it gets.

Good shootin'! -Al

 

[fm1947]

Al, Thanks, I thought there might be a specific thickness , now I understand, what would you consider safe or acceptable clearence.

 

[AlNyhus]

Frank, total neck clearances from .0015 (one and one half thou.) to .003 (three thou) work well. There's no upside to running tighter and we've seen a few 30BR's respond quite favorably after the neck clearance was increased from .0015. My recommendation echoes Randy's (.328 loaded round).

A good go/no-go guage is a neck bushing. I have neck bushings from .322 to .335 and routinely slip the appropriate size over loaded rounds to verify that they aren't too large. It's no substitue for a good quality micrometer that measures to the .0001 (tenth of a thou), but it's a dirt clod way of making sure you're not in trouble with necks that are too large.

Hope this helps. -Al

 

[fm1947]

Al, thanks again, I got it now, just was not sure I have a good mic and a go and no go gage and I am .328 , my problem has been measureing neck wall thinkness these dial gages and my old eyes just don't get it done.

 

[superlight93]

One thing I would like to add that was not mentioned is different size pressure rings between bullet makers. You stated your shooting Randy's bullets which is a good thing. BUT if you decide to experiment with another makers bullet, don't assume your loaded round will still measure .328 at the pressure ring. Always measure and don't assume. Good Shootin!

 

[RGRobinett]

One thing I would like to add that was not mentioned is different size pressure rings between bullet makers. You stated your shooting Randy's bullets which is a good thing. BUT if you decide to experiment with another makers bullet, don't assume your loaded round will still measure .328 at the pressure ring. Always measure and don't assume. Good Shootin!

Yes! Thank you 'superlight' - actually, my bullets are substantially 'fatter' than what I listed above! They are made that way, "for a reason". I didn't want to cloud the waters talking about parameters specific to my stuff: your statement, highlighted, above, nicely sums this up . . . wish I'd 'a thought o' that! :-[ RG

 

[fm1947]

Good info, I will measure when I shoot a different bullet, thanks everyone for the clarification.

Frank

 

[fm1947]

okay I returned all my brass 150 them, by mistake I turned some to .3271, but that was a good thing, I caught what I had did and corrected to .328, so I went to the range 100 degrees in Missouri, after a few warm up shots at 200 yards the ones at .328 shot 5 shot group at .6 of an inch if my calculations are correct that would be .286MOA , mirage was getting really bad , I am terrible at reading mirage so like a miracle it just cleared up, I shot 5 shots of the .327 how about .485 of an inch or .231MOA, I only had the .324 bushng I used on both. I need to do more testing with these 2 loads on a clear day but for now at 34.4 H4198 they are running 3050 , need to order .323 bushing, I ran out of BIB I was shooting another brand, I will be curious to see when the BIBS come how will do they have always shot better then this backup brand.

Thanks
Frank

 

[AlNyhus]

Frank, it's not unusual to see better 200 yd. accuracy in these .30's with more neck clearance.

Like around .003. Or more........ -Al

 

[fm1947]

Thanks Al,

When you say or more, how much more? I keep thinking some point that brass going to crack, I shot today first a 247 second a 248, but that won't get it, I got to get that 250.

 

[superlight93]

Frank,

Is that at 100 or 200 yds?

Keith

 

[fm1947]

It was a special match at 100 we did 5 then took abreak and 5 more from noon to 6pm normally we do 5 at 100 then 5 at 200, today is 200, I wasnt prepared for it , I was packing up after first 5 then a couple guys said you got 5 more , these guys are good at STL, there were 5 at least in first round all 250 and 4 in second round all 250and a bunch a 249, and it will be about the same today, I love shooting with these guys they make me a better shooter, I have only shot about 6 matches with these guys with custom guns all the other matches I have shot have been factory guns at a different club.

I have gotten better I can validate that by my scores and has cost a bunch, but being retired thats all I got to do.
I have learned alot, I been reloading about most my life 40+ years all handgun some normal rifle, I learned all of it from reading in here about precision reloading, case preperation, and all the other stuff that goes with it ,everything I learned about the 30BR was in the article that Al and Randy wrote and I am still learning, I shot pistol for many years and no one even cleans primer pockets, if it feeds it goes, you buy once fired brass put it in a progressive press and go , I could load 500 rounds for pistol to about 50 rounds for benchrest. and in USPSA you just leave your brass lay on the ground and walk away let the young guys pick it up, at the price of 9mm or 40SW its not worth all that bending over, at $25 to $30 a thousand why bother.

I won't make the match today I would like to but I am exhausted and it will be hot 98 degrees today and I would have to load about 50 more rounds I have 50 left over from yesterday and I would have to leave now at 6:30 am to get there on time its 1 1/2 hour drive, so next time they have this match I will know what to acspect.

 

[Shooter13]

Though 'neck-tension', bushing size, seating depth are not, "carved in stone", most barrels will provide TOP performance using 0.002" of total neck-clearance (in this case, a .328" loaded-round neck diameter, as measured across the heel of the seated bullet) and sizing with a .324" bushing. Often, less 'neck-tension' makes for somewhat poor grouping . . . but, all barrels are not created equal, so, some experimenting may be in order . . .

"but i used this formula 330-308=22/2=11" - assuming that you are experiencing disappointing performance, this could be a large part of your "problem". With a bullet sans a pressure-ring (rare on a custom, hand-swaged bullet - most will have a 0.0003" to 0.0004" pressure-ring), you are set up for ZERO clearance between the case-neck and chamber: you have a force-fit; your actual loaded-round neck-diameter (with a custom bullet) is probably about .3304"! ???

Again, while not an absolute, neck clearance ranging from 0.0015" to about 0.003" has a proven performance record. If you own a 30BR chambered barrel (.330" neck diameter) which does not shoot acceptably small groups, using the 'default' .324" neck bushing, .328" loaded round [neck-diameter], and a 'jam-seat', you have an unusual barrel - not necessarily a bad one, just somewhat out of the norm: you'll have to "hunt-up" what your barrel 'wants' . . .

MORE neck-tension is usually a good thing, less, not so good . . . but, either way, it appears that you NEED some clearance - .011x2= .022"+.308"=.330" . . . with a 'custom bullet, thus pressure-ring, you are forcing the loaded round - remember, about .3304" - into the [.330"] chamber. Good shootin'! RG

Yes I KNOW this is an old thread!
But as Mr. Robinett said about working the #'s for your neck here is what I finally did, BIB bullet is .3086 and if you only turn the neck to .010 you end up with .3286 in a .330 chamber!! So my necks are .0950 so with a seated bullet you get .3276 and working with a 323 and a 324 bushing to find out if it like .003 or .004. I had a problem using the .010 and ended up to fat (not me..well me too but the completed round.) So math really is your friend

 

[Dusty Stevens]

Yes I KNOW this is an old thread!
But as Mr. Robinett said about working the #'s for your neck here is what I finally did, BIB bullet is .3086 and if you only turn the neck to .010 you end up with .3286 in a .330 chamber!! So my necks are .0950 so with a seated bullet you get .3276 and working with a 323 and a 324 bushing to find out if it like .003 or .004. I had a problem using the .010 and ended up to fat (not me..well me too but the completed round.) So math really is your friend

You can do all the math in the world and thats a good thing. You can also take your mic over a loaded neck at the pressure ring and be done with it. Even calipers will yield the info you want with a quickness. I used to run .328 but went to .327 over a loaded bullet at the pressure ring. I use a .3255 bushing and its a done deal. I used a .326 bushing for the .328 measured neck. Live life simple- the 30br is like hitting the easy button. Of course do your own neck tension testing. Some like .001 some like .003