Not sure I needed one but I had a set of dies and picked up a reamer and I had an old Tikka M65 with a barrel that was pretty much used up so I had a new barrel installed and chambered for the 30 Gibbs. All the blah blah about how hard it is to form cases is a bunch of BS. Took 30-06 brass and ran it over a .338 expander. I just used my 338 AI dies because it has a tapered expander. Then ran that case through the 30 Gibbs sizer backed off 1/4 turn from touching the shell holder. This creates a shoulder that has some resistance when attempting to close the bolt. Load and fireform. Perfect 30 Gibbs case.For fire forming I started using IMR 4350 and 180 gr Speer bullets because I have a good supply of both. Started at 56 grs and worked up to 60 grs. 60 grs is not max in my rifle but that fills a std 30-06 case. My old crony says that load is doing around 2920 Fps. Even while fireforming cases that load is grouping into 3/4" at 100 yds.That is not a max load but I'm not sure I will go higher than that.2900 + fps with a 180 gr yields a little over 3400 ft/lbs of energy grouping into 3/4". I'm thinking that will make a dam fine deer rifle. Anyone else played with the 30 Gibbs ?

That is the way I form a lot of my Ackley Imp. cases, I have a few calibers.
I recently bought a 280AI and formed cases outa .270W Brass by seating the bullet out long (I really had to lay on the bolt handle to chamber the round) and the cases came out beautifully formed. The .280s shoulder is further foward than the .270W. You might want to try that method---easier!

Hip

I have a 240 and a 6.5 Gibbs. Both are easy to make cases for.
The one ting I found is the lack of sticky bolt lift. You need to watch primers and use common sense, as you can reach blown primers with no stickyness.

Still fireforming cases. Have tried some 150 and 165 gr bullets along with the 180 gr. 150 gr and 4320 grouped well but the POI was about 8" higher than the 180 gr. 165 gr bullets were so so but I havent found anything that beats 60 grs of 4350 under 180 gr bullets . they group into 3/4' with speer and Sierra bullets. I think I will just use that load and call it good.

quote:

I havent found anything that beats 60 grs of 4350 under 180 gr bullets . they group into 3/4' with speer and Sierra bullets. I think I will just use that load and call it good.

Sounds like the best plan

Gibbs got that claimed velocity with pressure, simple as that.. I went thru a Gibbs phrase many years ago and it was a pain in the kazoo.. He sold me a set of Gibbs Hydralic case forming dies to be used with 30 weight oil..filled the die with oil, insert the case, hit the plunger with a sledge hammer and you got a half formed case and oil all over the shop, on your clothes, on your boots, dripping down the windows, on the doorknobs and in your hair, ears and glasses,..at which point I decided Gibbs was a crazy son of a bitch and sold the whole project!! real story!!

Ray I think you were snookered. Necking up a 30-06 case to 338 then sizing it in a 30 Gibbs FL die is not a lot of work. I've done 150 cases and only lost a couple. The only thing I wish I had done differently is chambered the barrel in std 30-06 and worked up a max load and chronographed it THEN re chambered to the 30 Gibbs and chronographed the Gibbs load to see what increase I have.

there is a borelingly accurate formula to know if you are at the same pressure, assuming the case is roughly the same shape (bottle necked to bottle necked, straight walled to straight walled)

first you the change in case capacity, expressed in precent - say 12% which is quite a lot

and then divide that by FOUR -

in our example 3%

and that is the velocity gain you can expect AT THE SAME PRESSURE

The 30 Gibbs and 30-06 Ackley Imp are close enough in terminal ballistics to look at the ease in
fire formed cases along with use of loaded parent
06 cartridges.

My 06 Ackley produces about 185 fps over standard with 180 gr bullets. Close to 300 H&H velocities, and.... .5 MOA groups. It is an early custom
Mauser rifle that some riflesmith spent time on.

quote:

Originally posted by jeffeosso:
there is a borelingly accurate formula to know if you are at the same pressure, assuming the case is roughly the same shape (bottle necked to bottle necked, straight walled to straight walled)

first you the change in case capacity, expressed in precent - say 12% which is quite a lot

and then divide that by FOUR -

in our example 3%

and that is the velocity gain you can expect AT THE SAME PRESSURE

Then you have to add the "Cool" factor that the Gibbs case has over the standard, boring, .30-06 case.

quote:

Originally posted by jeffeosso:
there is a borelingly accurate formula to know if you are at the same pressure, assuming the case is roughly the same shape (bottle necked to bottle necked, straight walled to straight walled)

first you the change in case capacity, expressed in precent - say 12% which is quite a lot

and then divide that by FOUR -

in our example 3%

and that is the velocity gain you can expect AT THE SAME PRESSURE

Never heard of that formula but thats OK. First I have no access to any pressure equipment so all I have to go on is things like easy extraction no cratered primers and case head expansion. Without a doubt Gibbs pushed the envelope pressure wise. His data listed 64 grs of IMR 4350 with a 180 gr bullet yielding approx 3050 fps. Thats 4 grs more than I am shooting. One thing I have learned is that the shape of the case has nothing to do with the velocity. A fancy double radius shoulder adds nothing to a case of equal volume with a sharp shoulder or an equal volume case with a long sloping shoulder. So since there is very little 30 Gibbs data availible I was looking for other cartridges that could be referenced.. I used a fine ball powder to fill similar sized cases to compare case volumes. The 300 SAUM case held 75 grs filled to the case mouth. My 30 Gibbs fireformed cases held 76 grs and the 300 WSM case held 78 grs. So I simply used 300 SAUM and 300 WSM start loads and worked up for several different powder /bullet combinations. I never found any combination that grouped better than my 60 grs & 180 gr combination. I chronographed that load with with my old Chrony and the loads all came in at 2900 to 2920 fps. That is with the bullets .030" off the rifling. The loading manuals I have all show 60 grs of 4350 & 180 bullet in the 300 short mags yielding between 2900 and 2950 fps. So no I have not discovered anything new. I had some fun working up loads and fireforming cases. I ended up with a dam fine shooting rifle that delivers 300 short mag ballistics.It will not likely do anything a std 06 cant do but its giving me approx 150 fps more than the std 06 and Im happy with that.Happy enough that I will carry that rifle in deer season in 10 days time.

Well,
i didn't make it up - here's an article from 2005

quote:

Here we must remember that potential velocity only increases at one-fourth the rate of any powder capacity increase. The .300 Weatherby Magnum gains about 13 percent in powder capacity over the .300 H&H, which translates into a 3.2 percent gain in muzzle velocity, everything else being equal. This means that if a 180-grain bullet can safely be pushed to 3,000 fps in a .300 H&H, it can be given about 3,100 in the .300 Weatherby – in an equal-length barrel at the same pressure.

As you can see, 13%/4=3.2(5)%

https://loaddata.com/Article/B...proved-Cartridges/18

When i mentioned case shape, i said roughly the same -- in which case this article compares a 300 webby to 300hh -- bottleneck cases, the both of them.

but the REASON i mentioned that is you can't directly compare a new-fangled bottleneck case to a straight walled case - my 458 accrel, with roughly the same case capacity as the 458 ackley (just a hair more than the lott) or the same for my 470 accrel vs 470 capstick, again, roughly the same capacity, actually produce higher velocities with LESS powder than the straight walled cases -- and when reading the cases, the obvious signs (btw, i never posted any of the "dude, too much" loads), such as fully round primers, soot on the neck, etc, showed that the bottlenecked carts are more efficient that the same case capacity of straight walled carts.

has something to do with venturi effect, but that info is in cold storage in my mind, and not worthwhile to bring back up

point of the story, when you hear of 10%-20% gains in velocity off an improved version of the SAME CASE, most of that increase is, in reality, due to higher pressure --

there's some valid argument that an improved case can handle more/better pressure, but the context is pretty narrow - Ackley writes about this in his handloader guides, and iirc, it is mostly in the realm of weak locking actions (notice i didn't say weak actions), such as the 30-30 ai ... i could be wrong, it's been a few minutes since i spent much time thinking in the details, rather than the results

jeffeoso,
Never try to convince a wildcatter the gun he just tossed a ton of cash on a pink elephant, they will hate you for life!

Ray,
you know i've spent more than most on wildcats - if all i have to show for it is a (very)little wisdom, i think i'll keep that .

Heck, you've tried to convince ME to stop, in the past - didn't work then -- older and tired now

Well even if if Jeffeosso does like my 30 Gibbs it made a dam fine job on a nice 4x4 Whitetail at a little over 200 yds .Bang flop. About what my 300 short mag would have done

Congrats - sounds like a great hunt. you may have misunderstood me, as i like almost all wildcats, and the Gibbs are really neat in intent -