Info for 25 Gibbs

[cowboybart]

I acquired some 25 Gibbs dies, traded into a 25 cal barrel and plan on putting the rifle together this summer.
Any tips on making brass or loads? I plan on using 270 Win brass, unless that won't give me enough of a false shoulder.
What can I expect from the cartridge? Any load data out there?

 

[BIG D]

I had a 25 Gibbs. It took me forever to figure out what I was doing wrong while fire forming. I was just new to reloading in general and only played with 243 win up to this point. Basically what I learned the hard way over 4-5 years was the case head separation was due to not seating the Bullets long enough for a solid jamb in the lands. Once I figured that out it was easy as anything else. I would question using 270 brass because it is longer than 06 brass. As far as loads I don't recall. I do know I used 100 and 115 nosler ballistic tips and it shot pretty good. IMR 4350 was the powder I used. Run middle to upper charge weights for 25-06 as fire form loads and they shot pretty well also, just make sure to jamb the Bullets into the lands. This is acting as the shoulder to center everything up in the chamber since the shoulder is getting blown forward and the walls of the case are loosing the body taper. As far as load data it's really a crap shoot, basically just load off 25-06 data and work up till pressure signs and back off from there. I had mine on a Remington 700 with factory detachable magazines and feeding was ok but not as free flowing as the standard 25-06. As far as performance I wasn't overly impressed with it over the standard 25-06. The Gibbs was 100fps on average faster than the standard 06 but the best thing about the Gibbs was trimming was absolutely non existent! I do have some literature here but it's all scribbled on and I'm missing a couple pages. As far as would I do it again probably not. I've gone 6.5 for better Bullets but the 25 Gibbs does have that cool factor to it. I took the barrel off due to some pitting and its in my Gun room cabinet collecting dust. I've had 5 25-06 rifles since and they all have shot well. Idk if the 25 Gibbs is worth the extra effort to fireform or not. Depends on what your expectations are. Good luck and enjoy it. Jamb to fire form and load with 25-06 data for fireform loads. Then once fired you can start towards mid to upper 25-06 loads and work up from there while looking for pressure signs, sticky bolt, hard lift, flat primers etc.

 

[BIG D]

Oh and I forgot to mention, don't waste time with nickel brass it's prone for splitting while forming.

 

[Brians356]

Ken Howell in his book lists 270 Win as first option, and recommends "bulletless" fire-forming with pistol primer, after FL sizing in the 25 Gibbs die, and trim to 2.490". Ream or turn necks if necessary. If you lightly lube the case body with Rem Oil, and use enough Bullseye, you'll get sharp shoulders and no web stretching. Start at 10% of case capacity with inert filler, or 15% with no filler. I form my 250 AI "bulletless" and highly recommend it.
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[ireload2]

You might try making a tight fitting mandrel that will barely fit into the neck of a case when it is in the FL sizer.
This mandrel will be about .250 in diameter.
Use the .270 brass with the die backed up about .100 from the shell holder.

Be sure to keep the primer in your cases.
Fill them with water
Put a .005 or so feeler gauge under the case head.
FL size the case leaving the die .100 from the shell holder

Put the close fit punch in the case and give it a hard blow with a hammer to expand the shoulder.
It may take several hammer blows. The extra .100 will expand it a little too long.
After expanding some cases. Dry them with 90% isopropyl alcohol.
Then FL resize and see if you get a good shoulder.
Adjust your process until the hydroforming gives enough length to contract the chamber shoulder.

after you get everything working you should try to figure out where to trim the .270 cases.
When you fire form the cases expand like a balloon and the brass will get a little bit shorter.

 

[JohnKielly]

Sell the Gibbs dies & make a 25/06, or a .257 roberts.

 

[jasteinerv]

I acquired some 25 Gibbs dies, traded into a 25 cal barrel and plan on putting the rifle together this summer.
Any tips on making brass or loads? I plan on using 270 Win brass, unless that won't give me enough of a false shoulder.
What can I expect from the cartridge? Any load data out there?

Just joined. I have information requested, but this is a very old .25 Gibbs thread.

 

[Brians356]

... this is a very old .25 Gibbs thread.

"... there is no new thing under the sun."

Ecclesiastes 1:9
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