Home Forums Hunting & Shooting Custom Rifles & Wildcats 6mm Weatherby RPM 3600fps, 115gr Berger (pic)

I finally got a chance to toss some 6 RPM rounds over the chrono tonight. Best powder tested so far was VV 24N41. 72 grains tossed the 115 Berger out at 3600+fps.
Krieger 1:7 twist, 26.5" long.

Here are a few other powders I tried.

68gr H50BMG 3250fps
71.5gr US869 3500fps
73gr VV 20N29 3350fps

So lets get the "Barrel Burner" comments out of the way now. No need for that. Barrel burner, chamber 3 barrels at a time, the barrel will be worn out before you develop a load, throat eater, horribly inefficient, what can that do that my 6mm Creedmoor can't, solution looking for a problem......and the Campfire knuckle dragging drivel will go on and on. If that is all you have to say, just move along.

Tony Rumore
Tromix

pic left to right, .243, 240 Weatherby, 243 Catbird, 6mm Weatherby RPM

Edited to add - no accuracy testing. I was firing it on the 50 foot Tromix indoor range.

Nice. How fast you think it would push an 80 grain TTSX? That could be fun

Unfortunately, those bullets are at my other shop. The lightest I have on hand at the moment are 90gr ELD-X. They flew 3720fps with that same 72gr 24N41 load.
I imagine, I would need to go to US869 for the lighter bullets. There is more capacity with that powder than 24N41 which is about maxed out at 72gr.

I currently shoot the 85gr TSX from the Catbird at 3850fps with a 27" barrel (Sako AIII). My ranch is mostly timber, so the shots are not very long. That 85gr Barnes knocks the chit out of whatever it hits at that speed.

Tony

Might take a look at the 115gr nose ring dtac. I find this to be the most interesting Weatherby cartridge. A 108 or 109eldm would be nice too.

If only they made a 120gr eldm or tmk.

I tried the 108 ELD-M, but that bullet needs to be seated quite a bit deeper than the Bergers, at least with the current lead/throat in my barrel.
72gr of 24N41 launched it at 3590fps. No faster than the 115 Berger....but who really cares? It's going fast enough. I will probably throttle all the loads back for hunting anyway. No need to shorten brass life for a hundred fps.

Tony

Ross Seyfried and I did the 6mm Mach IV back in the late 80s.

A bit more powder capacity.

Would not recomend shooting game with the Berger at those speeds.

Have fun.

Are you necking down the 6.5 rpm brass in one step? Or incremental?

I can do it in one step, but I don't. I made a neck sizing die that brings it down to about 25 caliber first, then I made another die to go to 6mm. You can't use a .243 WSSM die to neck it down. The shoulder angle is wrong, so you only end up sizing the neck about half way down before the shoulder bottoms out. Ask me how I know. lol.

If anyone wants to make up a 6 RPM, you can get the reamer from JGS. Any .473" bolt face long action can run it and you will have plenty of head room to dangle the bullet WAY out off the case neck like the cool kids.

Tony Rumore
Tromix

I'd be curious what kind of accuracy that thing will produce once you get it figured out.
What kind of groups are you getting with the catbird with the 85g TTX?
As stated previously I'd avoid any projectile with lead in it for deer at those speeds......
Interesting project


dave

About an inch at 100 yards. The twist in the barrel is really too slow (1:12) to stabilize it past about 100 yards.
I need to make another barrel for that gun, but the 1:12 Hart blank happened to be on hand at the time.

Tony Rumore
Tromix

Welp cut that barrel down to 18.5” put a suppressor on it, stuff it in a hard case with a foam cut out for the rifle, scope, box of 20 and a flat brimmer hat with your choice of optics patch on the hat and call yourself ready. What else you got in the works?

Honestly that’s cool though. Always like seeing peoples projects.
S.

What action are you using and what scope do you have mounted on it?

Man, now that is a screamer. Cool project.

Your chronograph readings are suspect.

If it's truly stable at 100 yards then stability will increase farther out.

Isn't the catbird a Kenny Jarrett creation?
dave

I think you’re correct. Isn’t it the 280 Ackley necked to 6mm?

I had to read up on the RPM.
Interesting.
Does your reamer have the weatherby freebore?
Or did you shorten it?
dave

Kenny Jarrett's site says the Catbird is a 270 parent case with a 35 degree shoulder. So not a great deal of case capacity difference than a necked down 280 Ackley.

I did not shorten the lead or throat. With the Berger 115 seated to the base of the neck, it is just off the lands.
With the 108 ELD-M, I have to seat the bullet down below the base of the neck or the bullet gets jammed in the throat.

Tony

Could be. I'll try it on another conventional chrono as well as the Labradar.....if it will read it.
Quick Load predicted 3400fps, but it called out a bunch of powders that proved to be too fast burning.

Tony

That sounds a lot more in line. Interesting cartridge anyway, would be neat if there were some stoutly built 6mm heavy bullets to better handle the Big 6s.

Has there been any pressure measurements ?

Of course not. It's not slated for production by any means. There will most likely only be one made. Mine.

If you guys would like to just tell me how fast it should go, I will reduce the load accordingly, post those numbers for you, and everyone will be one little happy family.

Tony

You're the guy coming on here making wild velocity claims. This isn't 1960, we have the collective knowledge and software to pretty much predict right where a cartridge will perform, even if you choose to ignore it.

Your wrong about alot of things.
But your right about that..

dave

Sounds good. So how fast should it be going?

Quick Load already predicted powders that were too fast for the cartridge with charge weights that were way too high. If I used QL data, the primers would be falling out of the cases. Those loads were way over pressure before I even got close to the max suggested by QL.

I'm open to learning from you experts here. If you have a powder recommendation and or charge weight to try, let me know. I probably have it. Here's a pic of some that I have on hand....there's another wall full as well.

Tony

P.S. For whatever reason the 108 ELD-M's run way higher pressure and less velocity than the heavier Bergers. I'm sure you guys can tell me why.

I ran up two more powders tonight with the Berger 115. Shooters World SW50BMG and Reloder 50. Both petered out at about 3400-3450fps.

That's about all the powders available in this burn range area. I'm going to go back and retest 24N41. As much as I like to spar with you guys, the pressure is probably a bit high for any kind of decent case life at 3600fps, but I'll see with more testing. I have a feeling it will probably settle out at about 3450-3500fps without trashing cases. Then I'll machine a new barrel and test accuracy. I don't buy pre-fits wobbling around in a CNC chuck with a floating chamber reamer wobbling along with it.

Tony

Edited to add: I'll have some once fired brass for sale shortly. lol

Wow that's a fair selection of powder.
Have you measured your 6 RPM's case capacity?

Hal

Thought about a 25 rpm once. But this could be a fun one. Liking it.
I'd think you'd want to use some 4831 to get some case fill on that puppy. Maybe?

Have you given any thought to Hammer bullets?
dave

What about RL33, LRT or N570? Those three have been killers when I need a slow powder for Ultra Mags and similar.

What's the COAL in the 1st pic for the 6RPM?

Why would he handicap this cartridge with those?

In Quickload, are you adjusting the Ba Value in the Propellant Table Setup? There you'll be able to have it output the slowest burning available powders. Also, Quickload seems to often show higher charge weight estimates than reality, but the velocity estimates are generally closer to the ballpark. For those who might not be all that familiar with the program, it's really more for general estimates than actual load data, much as the disclaimer when one opens the program denotes!

As far as estimating velocity ahead of time, using "Barsness' Rules" to compare off of established pressure tested data for cartridges with similar capacity, bore diameters, and bullets will come up with a pretty close estimate on expected speed. In this example I'd probably compare it to pressure tested 6.5 RPM data, a larger 6 with tested Berger 115 grain loads, and perhaps published 257 Weatherby 115 grain data. Come at it from a few different angles and compare that with Quickload's estimates for the custom round design and you might even be on the basepath.

This stuff is all possible to figure out before firing a round, and really should be done beforehand to establish safety guardrails and minimize expense and time spent chasing one's own tail.

I'm not around my copies of JB's Gun Gack books where the The Rules are published, so will quote a post from RockyRaab about the subject:

I went ahead and backed all the loads down to 2900fps, so everyone should feel all better now.

Tony

What's the COAL of the pictured 6RPM/115 Berger?

Has anyone done a 6mm-7prc yet?

Tony

Thanks for sharing the information you have accumulated. I always learn something reading about the experiments of others.

This site is populated by some “gentlemen” who look for something to criticize.

West Texas Ordinance has data for a 25/7PRC.

The 7 Wby pushes a 120 at 3650 fps with 1/2 moa accuracy.

Why would anyone use a 120gr bullet in a 7mm?

I know there is no need for this cartridge but it sure looks fun. It should have a speed bump over a 240 which is ridiculously overbore so this would be an even less efficient case, but who cares. This look fun and made for the longest mono bullets.

I really like Nosler 120gr BT's out of my Contenders in 7mm TCU and 7-30 Waters.

Back to the 6.5 RPM as a 6mm. Awesome performance. Smart to try a variety of powder and bullet combinations then switch to the next barrel for the finalized load.

=============

Why shoot a 120 from a 7mm?

Before rangefinders and turrets, one of the ways to deal with longer shots was to use a lighter bullet for a flatter trajectory which worked if the wind was mild. I used a 120 nosler ballistic tip in a 7 Rem mag @ 3575 fps for coues wt. Did something similar with a 284 Win and a 100 gr original Barnes X bullets @ 3600 fps

I currently shoot a 120 NBT in that 284 @ 3450 for coyotes. No aiming compensation, just shoot at the yote anywhere from zero to 250.

Welcome to the future

I'd be interested to know what 6mm bullet actually works consistently on game at those velocities. Even at .240 Weatherby velocities normal cup and core and bonded bullets sometimes blow-up on bone, deflect off bone, pancake. The 6mm mono's have poor b.c's. and often aren't extremely accurate, pencil through lungs. If using it for longer-range like 600 yards, what bullets are going to be accurate enough at long distance for small game and perform well on game at longer distance, yet still work ok at short and medium distances at those velocities?

Pretty well documented, dtac 115gr nosering.

Bullets don't "blow-up".

Bullets can and do "blow-up", especially when they hit heavy bone at very high velocity - well-documented. Something doesn't need to have an explosive or incendiary material inside of it to "blow-up".

No they don't. That's fuddlore

You're a Rando internet retard with zero hunting experience.

Like a hog to slop, the fuddtard, aka gluckgluck4000 appears.

There's no retired sf dudes to blow in this thread, move along chubby.

He does have experience shooting game at long-range. Do you have as much experience at shooting game at long-range as he does?

Lol an appeal to chubbys "authority" lol.

Let's see some pics or evidence of bullet "blow up" after hitting bone......News flash, there isn't any.

John Burns' experience at shooting game at long-range is...relevant to the particular points in discussion. So, in your experience, no bullets rapidly disintegrate or rapidly come apart with pieces going in many directions when those bullets hit bone at very high velocity?

Bullets do not "blow up". When people claim this, it's because they don't know what they are looking at, if they're even looking at a wound. Most of the time it's assumption as they never recovered the animal.

And John Burns is irrelevant. In any discussion outside of distilled spirits.

Do some bullets rapidly disintegrate or rapidly come apart in many directions when they hit bone at very high velocity?

Fragmentation is not "blow up".

Rapid fragmentation of a bullet or rapid disintegration is commonly and correctly referred to as "blow-up". The relevant point wasn't the very restrictive meaning that you attribute to "blow-up" as opposed to a wider meaning, but that some cup and core bullets or even bonded bullets, rapidly fragment or rapidly come apart when they hit bone at very high velocity.

also known as "to grenade on bone" ie "blow up" ala explosive fragmentation

duh

Keep regurgitating fuddlore bulls hit....

Idiots claim this after they make a poor shot, with a gun they can't shoot, and never recover the animal.

Lol you believe bullets vaporize...lol

All the points in your last post are completely irrelevant to the point we were arguing. Perhaps try to be a little bit more intelligent so you don't lose complete credibility.

Any similarity here to "long range hunting"?

Jackson_Giving_Handys_To_Hobos might want to stay with her strength, Hobo Handys, and skip talking big game and bullets.

The poor girl has never shot anything including a rabbit yet wants to opine bullets with the grown ups.

you're a fkn idiot, plain & simple

Berger had issues with their 300 gr 338 cal bullet some years back, when bullet was sped up to a certain velocity level, the bullets never reached the target as they were simply wiped , vaporized .... Berger called it "nose slump" and redesigned the bullets to fix that issue

Imagine shooting a deer with that bullet at just under "vaporize" velocity and hit bone .... Bullet will come apart violently and disintegrate into tiny pcs with a shallow wound, I've personally had that happen on a bull moose at 100 yards with a 338 Edge years ago, hit it square in the shoulder and created a big mess of the front quarter but didn't kill it, second shot behind the shoulder went between the ribs and liquified the insides & killed it STAT, made it just past the ribs on the other side, creating another big mess, lots of wasted meat on that moose so I quit using them on short range hunts

Maybe the slow cartridges that you shoot aren't capable of "blowing up bullets on bone" and you've never experienced it

That simply makes you an ignorant fk, because you don't know wtf you're talking about

I guess we'll just agree to disagree

Even if you can't be honest with myself and the others on this thread, be honest with yourself. You were totally wrong as several on this thread have pointed out, so stop pretending that there was even a small amount of merit in your argument. A stupid person isn't someone who makes mistakes or who doesn't know something, it's someone who having made a mistake or having been corrected, continues to make that same mistake.

There really aren't any 6mm bullets that will stand up to the speed with consistent results and have high bcs. That's the problem with these sorts of rounds, and has been a problem with guys building screamers for decades, until bullet manufacturers catch up. Lately, the guys building 6mm UMs have done some farting around with nose ring bullets but the consistency isn't there; a big help is when using short suppressed barrels the velocity is often slowed down enough to provide more consistent results.
Regarding the bullet blow up deal, the process is well known in situations such as shooting light skinned varmint bullets designed for 222s speeds in big 22s, especially fast twist versions thereof. If one slows an SPSX down just enough to not turn into a puff of smoke on the way to the target, they can see some awful surface level wounds on coyotes when hitting shoulders. It's a bad deal.

The Fudd is strong with this one........

Every single time people believe a bullet "blew up" on a scapula, it's an assumption, because they never recovered the animal. Because the truth is they probably hit high, in the spinal processes. It's much easier to blame the bullet than their marksmanship.

You completely dumb schidt! The animal is recovered because you put a second shot into it. And even if you don't put a second shot into it, you can see (through your scope) the huge amount of blood at the impact point exactly where you aimed at, because the bullet has blown-up instead of making the usual nice clean entry hole.

I know I could and would. I'm not speaking about me. I'm speaking about the morons that shoot guns that "blow up" bullets. They can't see the bullet impact and rarely take a follow up shot. If you don't recover an animal and are simply going off of assumption, you are an idiot.



Watch the front face of the gel block. 99% of the time someone is looking at a dead animal and sees a massive entry wound, that's what happened. (It can be much more violent with more velocity and different projectiles)....but instead of using their brain to understand, they revert back to fuddlore...."bullet done blowed up!"

Carol Shelby once quipped "it's not how fast can you go; It's how fast you can afford to go". To each his own. I'm glad you like it.

Call it what you will, I call it bullet blow up. A 103eldx on the point of the shoulder at 3200fps.

You keep posting those pics. Explain what you're trying to say with them.

Is the top picture this inside of the front shoulder? What did the body cavity look like when the shoulder was removed?

That's an interesting round. What do you think of the standard 6.5 rpm? It didn't interest me much at first because I've never been a big fan of 284 style related rims but it has started to interest me more lately. It looks like the 6.5 will get close to 264 performance. I used to hunt a lot with a 264 years ago and it always worked well for me. A 6.5 rpm on weatherbys newer 307 action might be worth a look.

Lately the 6-06, 6.5-06, and 280 standard are appealing to me again on plain old 700 LA's. I like the open top port I can get my fingers in, the flat angle of ejection, the slick feeding of 06 cases and the box length for seating out. Had a chance to pick up a new model 700 sps in 30-06 in slc the other day at $440 hinged floor plate in Tupperware but the state background check was closed and I didn't run back the next morning. It would have made another nice donor. Maybe even for an rpm if they feed ok from 06 feed lips?

Bb

The bottom picture is the offside of the deer with the shoulder removed. Should be pretty self-explanatory by the lack of blood shot tissue that the bullet failed after hitting the shoulder socket. The original Nozler ballistic tip bullets would do the same thing. Match type bullets traveling at high velocity don't handle bone or penetrate very well. With that said, a match type bullet at high velocity in the chest cavity without hitting bone, the results are explosive dramatic kills. You might not have the dramatic kill shots using Barnes LRX or TTSX bullets, but you won't have any failures.

What did the chest cavity look like with the shoulder removed? What killed the animal?