My first moderate range hunting rifle was a 30 Gibbs. I have used one for several seasons and really like it. Ballistics with my 25" barrel were like the RSAUM, WSM. I shot 165gr SST molied over H4350, lit by CCI BR2 primers, in LC69 brass. Superbly accurate. Inside 500yds, wind will not be a big factor with this combo.
Fireforming the Gibbs brass does take a bit of work but cases last quite a while even at toasty loads. Case growth is minimal but I also used a Lee collet neck die.
I am very fond of this wildcat. I sold it to a 1000yd BR shooter and he has used it with good success in hunter divisions.
for longer ranges, the 165gr SST is not ideal due to lower BC. That is where the heavier bullets will help.
I now shoot a 6.5-06 because of the wind in the areas I hunt. Otherwise, I would still have that Gibbs. I didn't build a 6.5Gibbs because the sharp shoulder doesn't feed well in the controlled feed actions that I use.
just trying to find out exactly what is involved in making these cases, thats my only reason for asking about dimensions.
a detailed list of the steps needed to make these cases is what im after
Daniel J. Ludwig
From what I have delt with in making brass for the 240 Gibbs , after the brass is necked down to 6mm(not in your case) you find a load that is someplace mid range and use that as your fire forming load , when you seat the bullet it must be seated out far enough to hit the lands firmly so the case is not mover forward by the firing pin.
What you are doing is basicaly a big no no as you are firing a standard round in a chamber that has excessive headspace but that is how this case is made.
P.O.Ackley stated in his book that firing standard military ammo in the Gibbs chamber worked fine and he diden't loose any cases but he recomends seating the bullet out to the lands.
Now , unless you already have the 30 caliber barrel or you need the big bullet , I would recomend something like the 6.5-06 or even the 243 Ackley
But if your set on going with the 30 cal the 30-06Ai is hard to beat , that case combined with a 168-175gr SMK would make all the gun you need out to 1000yds , with a good 26" barrel a full case of R-22 or
H-4350 you should be able to creap up real close to 3000fps with the 175gr bullet. In short with good reloads you can pretty much get the same or real close to 300Win mag velocities with the 30-06Ai
What are the intended targets , just paper or are you gonna be shooting at game and if so what type of game. I've been shooting the 243Ai for a while now and have found it to be a great round out to 800+yds I haven't shot past that yet but I'm sure it would work well out to 1000 with a 105gr A-max. The recoil is mild and it doesen't get smoking hot after 5 rounds like some of the big mags do.
my entire intention with this project is to push a 165-168gr bullet up to or over 3150 with a standard boltface rifle, i dont want some super blah blah mag rifle to do it with, just personal preference, was originally going to build something like the 308 Baer or 300 Jarret, but i just cant justify shooting a quart jar of powder just to kill a WV whitetail that MIGHT way 150lbs on the hoof. im going to use either a 26" or 28" barrel, most likely a Shilen, and i will be using a Mauser action, converted to push-feed(have a Ruger extractor for a pattern)
i know that this isnt the greatest combo, but its the things i like, and i afford to do it this way. not to mention it will make me feel better to do it with something other than a Remington action, just dont wanna be a Sheeple on this one. guess im just opinionated.
Daniel J. Ludwig
I don't have a 30 Gibbs but just had a 270 Gibbs built. I got most of my information from a friend that had an old book on the Gibbs cartridges. The 30 Gibbs has a 35 degree shoulder and is longer than you said. Pac-nor has barrels already chambered for the 30 Gibbs. I had a reamer built for my 270 Gibbs with a longer neck so I could use 270 or 280 brass if I wanted too. I seated a Nosler 150 gr partition in a 270 case so it would barely fit in my magazine and sent it to Clymer to use as a pattern. All I plan on shooting is 150gr Nosler partitions. The fireforming was not too difficult once I got it figured out. You have to create a small shoulder to hold the case against the bolt. I tried new 30.06 brass by necking down to 270 Gibbs. I used 150 gr bullets (not partitions/too expensive) seated into the lands with a max 270 Win load. They didn't fully form and the necks were only about .21". I next tried new 270 brass necked up to 30.06 and then back down to 270 Gibbs. I necked the cases down to where they were a crush fit and seated the bullets to where they were well into the lands. The bolt is hard to close. On the first 10 shots 8 formed perfectly and 2 split the shoulder. I quit and went home. I emptied all the cases and annealed all the necks and shoulders. I went back and fireformed 40 cases with no more problems. The good thing about doing it this way is you can use the fireforming loads for hunting if you don't mind using a single shot (they're too long to fit in the magazine). This procedure should work with a 30 Gibbs also. Just size up larger than .308 and back down to 30 Gibbs to create a small shoulder. One problem I ran into on my Browning A-bolt is that I had to modify the feed ramp in my clip to allow for the shoulder being moved forward.
Dan , looking through my load logs for my 30-06Ai I see where I have run a 168gr silver ballistic tip out at over 3000fps with several powders one load I have listed is 64gr of H-4831 and gave a velocity average of 3118 out of a 26" Hart barrel.
My current pet load for this rig is a 180gr Ballistic tip capping off 63.5gr of R-22 for a average velocity of 3012fps and a velocity deveation of only 9 fps!! I remember squeezing another 2grs of powder in this load and it started to show pressure signs but the velocity was scaring 3200fps.
As for the barrel , I'd try to stay away from the Shilen. Save the money and get your self a Pac-Nor 1-12twist 3 groove , it'll clean easier , last longer and give you more velocity. If your looking for a prefit for you mauser action then I understand but still think you'ld be better served with a better barrel
i guess there would be alot less work in just chambering for the AI instead of the Gibbs. as for the barrel, will the 12 twist be enough for what im trying to do?? i dont guess the Pac-Nor is a bad deal, just alittle shakey about using a barrel i know nothing about, so im off to research, thanks for all the help.
Daniel J. Ludwig