30BR Neck Tension - Bushing Size

[gtbc82]

What do you find works best for neck tension - bushing size for a 30BR? Are you using a lot of neck tension, bushing .003, .004 less than the loaded round, or are you using a little .001, .002 less than loaded round. I know that Redding on their website is recommending using .001 less than loaded round, but I wanted to see what was actually working for people.

 

[gtbc82]

From the responses I have gotten it looks like .003 - .004 less is the norm. Another question I have is what is the normal dimension you turn your necks to? I just got into benchrest shooting and am still figuring a lot of this out. I have a .330 chamber and the first cases I turned I turned them to .093, so my loaded rounds measure .3268. Is .0016 clearance between the case and chamber too much? It seems like from most of the responses others are just under .001 clearance.

 

[jo191145]

Some free advice.
Don't let yourself get locked into any one ideaology on what the 30BR or any cartridge requires.
Nothing wrong with following trends. Nothing at all. Usually works.
But if the trend is'nt working don't be afraid to try something different.

As for the neck dimension. Your a little under norm.
Don't worry. If the gun is willing to shoot it will. That extra clearence won't stop it at all. Some folks have been switching to .003" total clearence and reporting benefits.
Your just a smidge over that. Might require a tighter bushing to follow trends but its just fine dimensionally.

 

[fdshuster]

gtbc82: Not suggesting you use it, just answering your question about what others are using. Chamber neck dia. is .330" from a Robinette reamer, outside neck turning Lapua to .010", sizing with the .324" bushing (Redding), loaded round neck dia. is .328". Works for me.

 

[LCazador]

Some free advice.
Don't let yourself get locked into any one ideaology on what the 30BR or any cartridge requires.
Nothing wrong with following trends. Nothing at all. Usually works.
But if the trend is'nt working don't be afraid to try something different.

As for the neck dimension. Your a little under norm.
Don't worry. If the gun is willing to shoot it will. That extra clearence won't stop it at all. Some folks have been switching to .003" total clearence and reporting benefits.
Your just a smidge over that. Might require a tighter bushing to follow trends but its just fine dimensionally.

This is great advice . The trends are set by the people that veered off the beatened path . Every firearm is unique ! After shooting for more than 50 years , I've found nothing is sacred 8) !!

 

[AlNyhus]

For neck tension, a bushing 004 under what a loaded round measures (over the pressure ring of the bullet) is where I'd suggest you start. Keep this bushing size constant as you tune the gun at first.

For neck clearance, anything from .002-.004 will give great accuracy. These 30BR's can at times get finicky when the neck clearance gets under .0015, especially at 200 yds. I use a bit more neck clearance than most (.003-.0035).

For seating depth, set the seater up initially to 'jam' the bullet .020 from when the bullet 'just touches' the rifling.

With this as a baseline setup, you can simply tune the gun with the powder charge until it shoots the best. Then, at that point you can change the seating depth in .005 increments. Once you've found the seating depth it likes, you can back off the neck bushing sizes by .001 increments.

H4198 is borderline for being too slow in the 30BR. The combo of neck tension and jam helps us get around this.

Hope this helps. -Al

 

[tenring]

I like .003" chamber clearance but jamb bullets just .010". If you run a full load of H4198 like most do, a too light neck tension will allow the bullet to back out partially after it is seated. I have been using a .323 bushing for a long time. Just recently switched to a .322 No improvement in groups, but bullets stay put.

 

[superlight93]

For neck tension, a bushing 004 under what a loaded round measures (over the pressure ring of the bullet) is where I'd suggest you start. Keep this bushing size constant as you tune the gun at first.

For neck clearance, anything from .002-.004 will give great accuracy. These 30BR's can at times get finicky when the neck clearance gets under .0015, especially at 200 yds. I use a bit more neck clearance than most (.003-.0035)

For seating depth, set the seater up initially to 'jam' the bullet .020 from when the bullet 'just touches' the rifling.

With this as a baseline setup, you can simply tune the gun with the powder charge until it shoots the best. Then, at that point you can change the seating depth in .005 increments. Once you've found the seating depth it likes, you can back off the neck bushing sizes by .001 increments.

H4198 is borderline for being too slow in the 30BR. The combo of neck tension and jam helps us get around this.

Hope this helps. -Al

Save yourself alot of money and frustration and listen to what Al is saying. The 30BR is the easiest short range cartridge to tune and it stays tuned!

 

[gtbc82]

Thanks for all the input. Now I just need to get out to the range and shoot.

 

[NCshooter]

For neck tension, a bushing 004 under what a loaded round measures (over the pressure ring of the bullet) is where I'd suggest you start. Keep this bushing size constant as you tune the gun at first.

For neck clearance, anything from .002-.004 will give great accuracy. These 30BR's can at times get finicky when the neck clearance gets under .0015, especially at 200 yds. I use a bit more neck clearance than most (.003-.0035).

For seating depth, set the seater up initially to 'jam' the bullet .020 from when the bullet 'just touches' the rifling.

With this as a baseline setup, you can simply tune the gun with the powder charge until it shoots the best. Then, at that point you can change the seating depth in .005 increments. Once you've found the seating depth it likes, you can back off the neck bushing sizes by .001 increments.

H4198 is borderline for being too slow in the 30BR. The combo of neck tension and jam helps us get around this.

Hope this helps. -Al

Hi Al, if the H4198 is borderline for the 30 BR, what other powder would you suggest?

Thanks, John

 

[AlNyhus]

John, the problem with using faster powders is that the next faster stuff out there is a pretty big leap. I've experimented with 4227 and it gives great accuracy at the very top end of the pressure curve. It's also very hard on cases. I've blended 4198 and 4227 but that's more trouble than it's worth, at least for me. N130 is another great alternative powder but its availability can be spotty.

Hodgden's H4198 Extreme is tough to beat, day in and day out. -Al

 

[NCshooter]

John, the problem with using faster powders is that the next faster stuff out there is a pretty big leap. I've experimented with 4227 and it gives great accuracy at the very top end of the pressure curve. It's also very hard on cases. I've blended 4198 and 4227 but that's more trouble than it's worth, at least for me. N130 is another great alternative powder but its availability can be spotty.

Hodgden's H4198 Extreme is tough to beat, day in and day out. -Al

Thanks Al. Have you any opinion on Benchmark?

 

[AlNyhus]

Thanks Al. Have you any opinion on Benchmark?

Benchmark is probably the most over looked powder for the 30BR. By the burning rate charts, you'd think it's too slow as compared to H4198. But in use, it's not as far off as the charts would lead you to believe. It packs in the case well and somewhere around 36.0 of it is where good stuff starts to happen with most 117-125 bullets....will be in the upper 2900's in most 17-20 twist barrels.

Good shootin'. -Al

 

[gunsandgunsmithing]

There is also n120 that fits between h4198 and 4227 in real world testing. I agree with Al...H4198 is borderline too slow for the 30BR, but it's hard to argue with the results. Still, one has to wonder about the mysterious vertical that I and many have seen with it in the morning, when temps are coolest. I've seen it too many times along the firing line...shots dropping out the bottom, for it to be coincidence. I saw this regularly with my 30 Major(grendel case necked to 30) too,with 4198. Switched to n120 and the morning time vertical disappeared in it. Haven't looked back since. n120 is pricey and is now only sold in 1lb containers, but it meters like water, is super clean, very consistent in every aspect, and seems to fit the bill nicely for me. And for reference purposes only, this combination helped me to finish in the top ten in 2009, and the top 15, in 2010, in IBS VFS benchrest competition points standings.

 

[GSPV]

Shhhh! We might need to get more one day!

Reloader 7 is another that worked for folks when 4198 got hard to find a couple of years ago.

 

[NCshooter]

There is also n120 that fits between h4198 and 4227 in real world testing. I agree with Al...H4198 is borderline too slow for the 30BR, but it's hard to argue with the results. Still, one has to wonder about the mysterious vertical that I and many have seen with it in the morning, when temps are coolest. I've seen it too many times along the firing line...shots dropping out the bottom, for it to be coincidence. I saw this regularly with my 30 Major(grendel case necked to 30) too,with 4198. Switched to n120 and the morning time vertical disappeared in it. Haven't looked back since. n120 is pricey and is now only sold in 1lb containers, but it meters like water, is super clean, very consistent in every aspect, and seems to fit the bill nicely for me. And for reference purposes only, this combination helped me to finish in the top ten in 2009, and the top 15, in 2010, in IBS VFS benchrest competition points standings.

Hmmmm, what's your load with the N120? Primer choice?

Thanks

 

[gunsandgunsmithing]

There is also n120 that fits between h4198 and 4227 in real world testing. I agree with Al...H4198 is borderline too slow for the 30BR, but it's hard to argue with the results. Still, one has to wonder about the mysterious vertical that I and many have seen with it in the morning, when temps are coolest. I've seen it too many times along the firing line...shots dropping out the bottom, for it to be coincidence. I saw this regularly with my 30 Major(grendel case necked to 30) too,with 4198. Switched to n120 and the morning time vertical disappeared in it. Haven't looked back since. n120 is pricey and is now only sold in 1lb containers, but it meters like water, is super clean, very consistent in every aspect, and seems to fit the bill nicely for me. And for reference purposes only, this combination helped me to finish in the top ten in 2009, and the top 15, in 2010, in IBS VFS benchrest competition points standings.

Hmmmm, what's your load with the N120? Primer choice?

Start at 29.0 grains with 110-118 gr. bullets. This is with my 30 major, which is abou 2grains smaller in capacity than the 30br. I like 205m primers but have tried most all of them with good results.

 

[GSPV]

Mike,

Is that enough leeway with naked bullets? I shoot 30.8 of N120 with HBN coated bullets in my Major.

Greg J.

 

[gunsandgunsmithing]

Mike,

Is that enough leeway with naked bullets? I shoot 30.8 of N120 with HBN coated bullets in my Major.

Greg J.

Good point Greg. I'm running the same load with danzac coated 118's for the most part. I changed the starting point to reflect your point. Every barrel is different though, and I've not shot that light in a long time, but better safe than sorry.

 

[NCshooter]

Mike,

Is that enough leeway with naked bullets? I shoot 30.8 of N120 with HBN coated bullets in my Major.

Greg J.

Greg, I may be dense here but what do you mean by "leeway"?

Also, my 30 BR rifle is new and I'm thinking about coated bullets. Never used any for my 6 BR shooting but I'm beginning to learn that many 30 BR shooters use them.

Which of the coatings/processes do you recommend? I have a thumbler tumbler by the way.

Thanks - John