IBS Short Range Caliber Limit?

[Joe Woosman]

Hi all. It's been awhile. Seems to me the IBS caliber limit was .40 in the past. I read through the newest rule book a few times and the only place I saw a caliber limit was in long range benchrest, and that was .40. Does that also apply to short range or has something changed?

 

[Joe Woosman]

So it sounds like there is the potential if one were to build a competition rifle something larger than 30 cal you might not be allowed to compete at an IBS registered match if the range says you can't. Hmmmmm.

Do you know if these ranges make exceptions for low energy cartridges such as a Marlin 44 mag lever gun? Or is it a cut-n-dry limit?

 

[Butch Lambert]

A few Varmint for score rifles were built a few years ago in Texas up to 45 cal. They didn't work.

 

[R.G. Robinett]

Hi all. It's been awhile. Seems to me the IBS caliber limit was .40 in the past. I read through the newest rule book a few times and the only place I saw a caliber limit was in long range benchrest, and that was .40. Does that also apply to short range or has something changed?

A few years back, at a registered IBS tournament, I enjoyed a morning occupying a bench adjacent to a fellow who chose to employ a 460 Weatherby Mag. - had he been able to keep his shots inside the numbered "boxes", or even [reliably] hit his 100 Yd. target card, my tolerance level would have increased (a little maybe ) . . . thankfully, prior to the end of the 100, he ran out of ammo! So, that's my long-winded answer - I don't think there is a limit - at least, at that time, there was not. RG

 

[Joe Woosman]

A few Varmint for score rifles were built a few years ago in Texas up to 45 cal. They didn't work.

Do you happen to know what was used for bullets?

 

[jackie schmidt]

Joe, back in the late 90's, Eric Klemetich, (who passed away several years ago), did a project with 44 caliber bulets, which measure .429.

He took a 6 BR case, necked it up, and headspaced it on the mouth of the case like a 45ACP does. He build an all out Benchrest Rifle, Panda Action, Krieger Barrel, etc. He had dies made, went first class all the way.

He was using the Sierra Match bullets, and some other brands. I forget what the twist was, somewhere in the 1-20 I think.

It all came together real well, everything functioned as it should, the only problem was it would not shoot much better than about 2 inches at 100 yards. He put about as big an effort into the project as one could, it just didn't work. He finally scrapped the entire project.

Eric was quite the character. You never knew what he was going to come up with............jackie

 

[Joe Woosman]

Sounds like they must have been pistol bullets. My concept is a .40 cal machined bullet with a bottleneck case. Low velocity with comparable recoil to a 30BR. Should I not waste a bunch of time and money on it?

 

[Jim Bailey]

Remember,

Charlie Hood's "cookie cutter"? Wonder if there are any photos out here?

 

[Jeff Stover]

Joe - hello.

The only caliber restriction I can find in the rule book is 1000 yard. You have to be .40 or smaller.

jks

 

[Butch Lambert]

Joe, He wasn't shooting pistol bullets. He had a first class operation going. He knew if he went with the larger cases THE RECOIL WOULD HAVE KILLED HIM.

 

[David Halblom]

there are still

I seem to remember that back in the late 90's there were some BR experiments using .338 dia and .358 dia bullets for score shooting. Supposedly the cores were made out of soft swaged aluminum in order to keep the weight and recoil down. The problem was that no one was making BR match quality jackets at the time, so accuracy was so-so at best. Anyone else know anything about this effort?

Zdog (Chris Mitchell)

NO BR quality jackets made for anything but .22, 6mm, and 30 caliber. And, so far, machined copper bullets have proven to be just as problematic as "factory" jacketed bullets. The will shoot "minute of deer" but not sub-minute of angle.

Take a good look at a score target. In order just shoot a 250-0X, your rifle MUST shoot at least in the .4xx's. And a 250-25X is in the low 2's. And if you are going to chase the current NBRSA record for VFS of 250-25X-17 w/o or IBS of 250-25X-21 w/o, your rifle will need to consistently agg in the high 1's. You are not going to do this with factory bullets.

 

[Joe Woosman]

Take a good look at a score target. In order just shoot a 250-0X, your rifle MUST shoot at least in the .4xx's. And a 250-25X is in the low 2's. And if you are going to chase the current NBRSA record for VFS of 250-25X-17 w/o or IBS of 250-25X-21 w/o, your rifle will need to consistently agg in the high 1's. You are not going to do this with factory bullets.

Not sure how you are coming about your math there. A .500 ten ring plus a .308 bullet = .808. Not that you will likely be shooting those scores with less accuracy than you stated but it is possible.

I'm thinking I should probably start by machining some bullets for a 30BR to get an accuracy comparrison.

 

[David Halblom]

Not sure how you are coming about your math there. A .500 ten ring plus a .308 bullet = .808. Not that you will likely be shooting those scores with less accuracy than you stated but it is possible.

I'm thinking I should probably start by machining some bullets for a 30BR to get an accuracy comparrison.

The math comes because the bullet diameter means nada. You only have the strike circle of whatever bullet you use. All the centerfire score games are best edge scoring.

 

[tobybradshaw]

The math comes because the bullet diameter means nada. You only have the strike circle of whatever bullet you use. All the centerfire score games are best edge scoring.

Bullet diameter DOES matter for score shooting. Imagine a .308 bullet in the 9-ring that barely grazes the 10-ring. With best-edge scoring the .308 scores a 10. Now put a 6mm bullet in the center of the hole made by the .308 -- the 6mm gets a 9 because of the ~0.032 of white between the edge of the 6mm bullet and the 10-ring.

If bullet diameter didn't matter, everyone would shoot the cartridge with the greatest inherent accuracy at the chosen range in best-edge score games.

It is perfectly possible (however unlikely) to shoot a 250-0x at 100 yards with a group that would measure 0.808", as long as you're shooting a .308 diameter bullet or larger.

 

[David Halblom]

Please, by all means

Bullet diameter DOES matter for score shooting. Imagine a .308 bullet in the 9-ring that barely grazes the 10-ring. With best-edge scoring the .308 scores a 10. Now put a 6mm bullet in the center of the hole made by the .308 -- the 6mm gets a 9 because of the ~0.032 of white between the edge of the 6mm bullet and the 10-ring.

If bullet diameter didn't matter, everyone would shoot the cartridge with the greatest inherent accuracy at the chosen range in best-edge score games.

It is perfectly possible (however unlikely) to shoot a 250-0x at 100 yards with a group that would measure 0.808", as long as you're shooting a .308 diameter bullet or larger.

Tune your rifle to a .800 agg. I will defy you to shoot a 250 at that point

 

[jackie schmidt]

Tune your rifle to a .800 agg. I will defy you to shoot a 250 at that point

+1

 

[tobybradshaw]

Tune your rifle to a .800 agg. I will defy you to shoot a 250 at that point

Hence "unlikely," as I said.

If bullet diameter doesn't matter for score shooting, as you claim, then why the 30BR in VFS but not (often) in top-level group shooting -- a venue where bullet diameter truly doesn't matter?

E.g.,

http://benchrest.com/showthread.php?84762-2012-NBRSA-Varmint-For-Score-Nationals-Equipment-List

http://benchrest.com/showthread.php?75153-SS-Equipment-Lists-(Helping-James

 

[steve stanley]

This particular horse has been beat before, theoretical and real life are totally different things. A 250 with a .400 tuned rifle would be luck.

 

[Joe Woosman]

This particular horse has been beat before, theoretical and real life are totally different things. A 250 with a .400 tuned rifle would be luck.

I don't agree with that at all. I dare say it's been done many times. A .400 tuned .308 only needs to be steered to an accuracy of about .400 to hit all tens.

Am I correct in my assumption this topic is not welcome?

 

[Greyfox]

I don't agree with that at all. I dare say it's been done many times. A .400 tuned .308 only needs to be steered to an accuracy of about .400 to hit all tens.

Am I correct in my assumption this topic is not welcome?

Joe,
I don't know that it is unwelcome, it's just that those of us who have shot score for quite a while can clearly see that you are unclear on the concept. In the first place, a 250 @ 100 yds won't get you anything and a 250 @ 200 yds with a rifle that will only shoot .400 is a near impossibility. Even a 250 @ 100 with a .400 rifle is very unlikely and will be the product of luck. If you have a 4/10ths variance in your POI, you will be all over the place on the target.

BTDT,
Rick