weatherby cartridge

nuclabuyer

I was wondering if the neck on a weatherby would be more efficient if it was tapered like an AI neck as opposed to the round sholders standard to weatherby. I just bought a 30-378 and was just curious to know if a 30-378 AI (dont even know if it exists) would be a better performer for the powder then a standard 30-378

just a question

thanks

Guns & Glass

Simply, no.
> AI necks in high pressure cartridges can be difficult to extract.

> Powder gain virtual waste.

> Last but not least, Weatherby double radius shoulder internally acts as a venturi boost. N/A w/AI taper.

nuclabuyer

I was just wondering if the rounded neck or a weatherby case is a performance reducer and if a straight neck would help increase velocity

sandwarrior

nuclabuyer,

I think that is what guns & glass was saying. It enhances performance by smoothly moving all the pressure forward from the chamber out into and down the barrel. There is an overcharge of powder in a Weatherby to keep the bullet pushing down the barrel. Weatherby also uses freebore at the leade to let the bullet get up to speed before it hits the lands.

There is also so much pressure in a Wby case that to dam it up like an AI case would cause an explosion. Again, NO it won't work and you don't want to make it work.

nuclabuyer

The reason that I am asking is because there is a barrel for 400 dollars that has that feature http://www.gunbroker.com/Auction/ViewItem.asp?Item=85566743
He is claiming speeds of more then 4500fps with a 180 gr bullet from what he is calling a 30-378 weatherby IMP. Does that mean that he is incorrect?

Just trying to figure out why you would by that, and I dont have any free bore because it is a Sako 995

Cyclonus

Im not a 100% sure but dont they have longer barrel life because of that as opposed to a more bottlenecked round.

1KYDSTR

WOW! If you are using a Sako barrel with minimal freebore...you won't last long. When I read the guys auction, he does not state that there is longer than standard freebore, but I would ask! And I am pretty sure he will tell you that indeed, there is longer than normal freebore in that "Smith" cartridge. Roy designed the freebore in there so that the pressures would stay low in the chamber and leade, and the reciever would be less stressed. In other words, the pressure spike is spread out over a longer area, thus reducing the peak pressure in any given area of the barrel shank. If you go jamming that 180 grainer into a standard leade pressures will spike GRIEVIOUSLY and almost ceratinly result in a reciever failure, and a trip to either the Hospital or worse, the morgue.
My take on it is that the "Smith" cartridge uses that parent 30-378 case with the square shoulder (45 degree, I think...just an AI kind of thing) just for it's voluminous case. You can jam a butt load of powder into one of those, especially if AI'ed and squared up. He also says it is "long chambered", which means it needs to be finish reamed and then the lead adjusted. If you get it, pay the extra money to have it finished correctly by someone who evidently (from the sounds of his ad, anyway) has molto experience with this conversion. Also...invest in one hell of muzzle brake...you'll need it in anything chambered onto a 700 or comparable action as the recoil with a 180 grainer will be astonishing. Also he said the longer barrels were getting 4500+...not the length he is offering, which supposedly makes it up "over 4000+ fps"...either way that sucker is really moving for that bullet weight!

sandwarrior

nuclabuyer,

This seller is making a lot of claims that I don't think are maybe true. Number one is the velocity. Most 30 cal bullets aren't made to handle 4000+ fps. FMJ's and Barnes maybe, solid copper manufacture maybe. There is such a thing as the Hague convention and last time I checked we are still pretty much abiding by it, or at least the spirit of intent of it. So the Barnes will be ruled out. The standard FMJ's haven't shown themselves accurate enough to warrant making this system a reality. If there are custom made solid copper, non-expanding bullets being made, that could be a reality but I have no idea who would be doing it.

Put in a different light you can make a AI out of Weatherby case. No it still won't be efficient. You will then need to modify your load so that you don't overcharge the case. Whether you use the Freebore concept or not, you will need to seat bullets for the way you've throated your rifle.

The biggest reason I find this to be not really true is that in order to have accuracy you have to have consistency. At the velocities that seller speaks of you will go through barrels like no yesterday. Changing barrels on a rapid basis isn't going to help with consistency. One of the biggest reasons the U.S. is still on the fence with the .338 Lapua is because they are only gettting about 600 rounds through a barrel. They are only pushing 250 gr. bullets with that out to 3000 fps. The other thing is bullets are very heavy and efficient for caliber. The 180 gr. bullet isn't that heavy or efficient. It's good out to a reasonable distance. Beyond that they don't remain as accurate.

I won't say it can't be true, but if it is, it certainly flies in the face of a lot of good work that is finally being accepted.

EDIT:

nuclabuyer,

What I'm hearing you say is you want more velocity than what you have. You can do that up to a point. One way to get it is to increase case capacity, another is to increase case pressure, a third way to increase barrel length. Any of these will work up to a point. What I'm saying is that you can do this just know the drawbacks and the limits. The drawback of the first two is more recoil and lower barrel/chamber/case life. The drawback of the third is a long barrel not convenient for hunting. Honestly what your hunting in you don't need that much extra velocity. If it's thick and wooded why would you want a 4K fps round? If you are out west where it's open what does it matter about having a long barrel? Still a 4k round isn't necessary. If you want long range the key to that is ballistic efficiency with your bullets. For .30 cal that starts at 200 gr. and up. I push 208 Hornady A-max's at 2790. That's plenty fast enough to take advantage of what the bullet can do. If you want faster go ahead. But, I guarantee you you will get nowhere near 4K with that weight pill in .30 cal. And, it's not necessary.

nuclabuyer

So the only way to get the higher velocity then would to go to say a 30 - 32in barrel or something like that. Not particularly the best carry to go hunting rig, but If I do that it becomes a little more efficent for a long rang hunting rig. I dont plan on shooting hundreds of rounds thought it, I have a 300 that I keep up on my long range shooting, and would problay use that instead of 30-378 for 11 months a year and then in hunting season shoot 15 or so and make sure that all is well with the ballistics chart from 100-600 for hunting season. I shoot my 204 alot at 400 so I got really use the setting for wind and drop compensation because the wind really plays with a 40gr bullet. and with a 30in barrel i would move up to 200 gr bullets, I read on i think Chuck Hawks website the over 180gr bullets is where this particular rifle comes to life

JustC

the 30-378 is already wayyy overbore. There is a ton of powder space left at a max load,..so increasing case volume will still result in a cavernous case with a lot of air space left over,..and shorter barrel life with an even increased erosion rate. I considered the 30-378 but the 300RUM is right on it's heels with less powder burned because it is more efficient.

nononsense

nuclabuyer,

"I was wondering if the neck on a weatherby would be more efficient if it was tapered like an AI neck as opposed to the round sholders standard to weatherby."

The original venturi neck and shoulder on the Weatherby cartridges is very efficient and you do NOT need to consider having the chamber 'Improved'. The Improved case will NOT increase any performance without substantially increasing the barrel length to the point of being difficult to use in the field. From the bench is a different story. A 27-1/2" barrel will not utilize the case capacity of the original case let alone a case that has been truly 'improved'.

The original .30 Smith is a standard length (2.500") belted magnum case that has had the neck lengthened by pushing the shoulder back. It has a capacity of approximately 70 grains of water by measurement.

I have sent an e-mail to the seller with a list of questions but I haven't heard back from him as of this post. If I hear back from him, I'll amend this post as an update.

In my opinion, there are better choices to make.

Good luck with your decision!

Best.

ADDED:

The seller responded to my e-mail and as I thought, he is merely a seller and has little technical knowledge of what he is selling. The interesting part is that I know OF the gunsmith that supposedly makes these for the Federal Government...

The seller suggested that I call said gunsmith about the technical details and claims but that I "should be prepared to buy" instead of just wasting the gunsmith's time...

I think I'll write another e-mail to the seller...

Best.