Re: 6.5 gibbs dimensions?

16 March 2004, 06:29

Just curious, but is that the same as the .256 Gibbs, favoured by British sportsmen in the 1920s and 30s?

George Gibbs had his works in Bristol UK, near my home. The Gibbs name is currently owned by Crudgingtons of Bath, again, close to me.

I saw an original .256 Gibbs at an auction last week. Sweet looking rifle.

What sort of velocities do you expect to get?

16 March 2004, 07:01

ramrod340

Nope,I believe the 256 Gibbs, 256 Gibbs Magnum and 6.5X54M-S are the same round. Case capacity is about 54grs of water. The 260Rem is 56gr of water.

The 6.5 Gibbs is a blown out 06 with the shoulder moved forward. Capacity is around 73grs of water.

16 March 2004, 08:59

TSJ

rogerinneb
throw me an address and I'll send you an empty case if you want. My Gibbs will do 3500 fps with a 120 Nosler SB with a 27" Lilja barrel.

16 March 2004, 09:12

ramrod340

What powder do you use?

16 March 2004, 16:59

HockeyPuck

Please keep in mind that the reamer dimensions are for minimum chamber, which is larger than maximum cartridge. For the English gentleman, the Gibbs being discussed are wildcats originated by Rocky Gibbs of the US.
Regards,
HockeyPuck

15 March 2004, 15:41

rogerinneb

Anyone know of a website that would show the chamber/case diagram/dimensions for a 6.5 Gibbs?

Thanks!

15 March 2004, 17:01

ramrod340

Clymer shows it on the site. Look under reamer design.
http://www.clymertool.com

Basically take an 06 blow it out to .455" at the shoulder. The shoulder starts at 2.145" 35 deg shoulder and the neck is approximately .25". Trim length is 2.502"

15 March 2004, 17:51

rogerinneb

thanks ramrod, any load data?

16 March 2004, 02:55

ramrod340

Send me an email and I'll send you a copy of the article written on the 6.5,7 & 8mmGibbs.

16 March 2004, 04:17

Wapiti

Quote:

Send me an email and I'll send you a copy of the article written on the 6.5,7 & 8mmGibbs.

Ramrod I would be interested in that info on the 8mm Gibbs if you would be kind enough to forward it to me?

Thanks, Wapiti

16 March 2004, 05:27

ramrod340

Just send me an email and I'll attach the file and return.
ramrod340@hotmail.com

17 March 2004, 11:24

Deerdogs

I take it that George Gibbs is no relation to this young upstart Rocky Gibbs

.

Thanks Guys. We live and learn.

17 March 2004, 19:14

rogerinneb

My reason for inquiring is a bit odd. I had a Sako long action built into a 6.5x06 (with a 28" very heavy Krieger barrel and a McMillan stock) by a gunsmith I wish I had never met. He is now in jail.

My first trip to the range with loads of 4831SC and 142gr. SMK's (charges from 47-50 gr.) were showing flattened primers. The groups got smaller as the charge went up, with the 50gr charges showing good promise at about 5/8" at 100yds for five shots.

Upon returning home I was looking at the fired case and realized I had a MAJOR headspace problem. The necks were moved forward about a tenth of an inch!

I took the gun to another gunsmith with a couple of fired cases, one of which I sectioned to look at the web area. After a fair amount of discussion he remarked that it was very close to 6.5 Gibbs, but the shoulder isn't quite as sharp. He showed me how to initially size the cases so they would headspace at the neck juncture so I could safely form the cases.

Anyway, I'm trying to figure out where to go with the H4831sc. Looks like I can work up towards 53gr pretty safely and I'm going to try some H1000. I'm sort of extrapolating between 6.5x06 loads and 6.5x06AI and 6.5 Gibbs data.

I know there are more scientific methods (grains of water, quickload, etc.) but I'm not a dedicated wildcatter so I'm not sure how to proceed and I don't have the software....

I know I could have the thing rechambered but I've already sunk so much damn money into this thing..and I'm kind of intrigued with my weird wildcat....

Whew.....

Roger

18 March 2004, 02:41

Rojelio

Hi Roger, what bullets were you using in your initial tests and do you have any idea what kind of velocities you were getting. The reason I ask is that I have a custom 6.5-06 in the works. So far I have the barrel and stock. I'm waiting for a stainless Charles daly action which according to their website will be in August. Thanks, Rojelio.

18 March 2004, 03:09

ramrod340

Roger,
If it is true Gibbs capacity then with H4831 and a 140 the charge starts at 52.8 and increases to 59. If you would measure the capacity of the formed case in grains of water I would be happy to run it through Accuload.

18 March 2004, 08:05

rogerinneb

Thanks a bunch ramrod...If the procedure is to fill the case to the top of the neck (full, in other words) the capacity in grains of water is 70.2......I'll try and post some pictures of some cases for everyone's curiosity...the (almost) famous "6.5 rogerinneb."

18 March 2004, 08:57

ramrod340

Yep I think you have your own new wildcat. LOL The Gibbs has a capacity of around 73.3 the AI around 72.2. A straight 6.5-06 is closer to 67grs. These will vary a little based on brass. I didn't keep your email. So send me an email with the bullet(s) and powders you are interested in. I also need your COL. For other combination with a capacity that close to the 6.5-06AI you could use it just as is. Hornady will make you dies for it for around $95.

18 March 2004, 12:06

rogerinneb

Case on left is new Lapua 30.06

Case in middle is FL sized in 6.5x06 die

Case on right is once fired....

See what I mean?

18 March 2004, 13:16

ramrod340

Looks to me like he just ran the reamer in to deep. That appears to be a normal 06 shoulder.

18 March 2004, 17:39

rogerinneb

Ramrod,

I agree. The shoulder angle looks unchanged, as it does on the chamber cast I did with Cerrosafe. One thing I noticed from the chamber cast, it appears that the necks could stretch a mile and not need trimming. This gives me the idea that maybe I should use .270 brass because it's longer and would give the neck a little more surface area to grab the bullet. The throat was set so a 120 gr. Sierra MK would be able to touch the lands and seat flush with the base of the neck. 140's seat to about the body/shoulder juncture.

I guess my next question is for the gunsmithing forum...how expensive to pull the barrel and turn it down so that the damn thing would be properly headspaced for 6.5x06?

Bullet wise I'm looking at the 95 gr. vmax, 120 Gr. Sierra Match King, 125 Nosler part.and 142 gr. Sierra Match King.

I have N160, 4831SC, H1000, H450. If other powders would be accurate I would buy them.