Bought my first big bore, 505 Gibbs. Looking for load data/advice

[mchammah28]

Hello all,

I'm excited to be here. Just bought my first big bore in 505 Gibbs. It's a Montana Rifle Co. DGR. I'm looking for advice and recommendations on load data. I know the original Gibbs was recommended to cap at 40 kpsi of pressure, but could one load slightly hotter? Do any factory rounds push a 600gr bullet past 2200 fps?

Theoretically with modern norma brass and powders, achieving 2300 fps with a 600g bullet is doable. My Montana Rifle Co. Action can certainly handle the pressure. Any advice or insight is greatly appreciated.

 

[zephyr]

I'm loading 525gr CEB Solids at 2300 fps
and Welcome

 

[Tintin]

 

[RR 314]

Dang, you are excited! Hope your excitement doesn’t wane during load development. . I stopped just under 2300 with 525 gr. TSX and RL22 . . . and then sold the damned thing.

 

[freefall]

Have fun!

 

[mchammah28]

Dang, you are excited! Hope your excitement doesn’t wane during load development. . I stopped just under 2300 with 525 gr. TSX and RL22 . . . and then sold the damned thing.

I hope so too!

 

[RR 314]

I hope so too!

Go big or go home. You are the only person I know to start off the big bore game at .505! Well, I guess you could have gone .700. Tuned in for first report!

 

[krish]

No need to push it that hard. 2100ft/sec will do all you want. Yes it can be pushed to 2400 to 2500 ft/sec. But why. It is meant to be 100yds or less for DG cartridge.. it is not a sniper rifle.
Krish

 

[freefall]

Go for it, snipe the T-Rex from 800 yds!
God don't love a coward!

 

[mchammah28]

No need to push it that hard. 2100ft/sec will do all you want. Yes it can be pushed to 2400 to 2500 ft/sec. But why. It is meant to be 100yds or less for DG cartridge.. it is not a sniper rifle.
Krish

600 grains @ 2500fps would be punishing. I've shot a 460 weatherby w/o muzzle brake and it was unpleasant, I can only imagine this load. And 2100fps is more than adequate, I'd just like to get over the 2200fps mark to squeeze a bit more out of it ballistically. I realize this sounds like I'm splitting hairs, because I am haha. Truth be told, I prefer a lighter bullet flatter shooting than a heavy slower bullet. If I can get the 535g to 2500 fps that would be great.

 

[colorado]

I've loaded 570g TSX's in my 500 Jeffery to 2510 fps. Recoil was unpleasant. I've settled on a sedate 2300 fps.

 

[freefall]

sedate.

 

[mchammah28]

I've loaded 570g TSX's in my 500 Jeffery to 2510 fps. Recoil was unpleasant. I've settled on a sedate 2300 fps.

Magnificent. I could have this wrong, but my understanding is the Gibbs case is actually generous, however the old Kynoch loads with cordite were designed to operate at 40ksi. This 40ksi pressure limit is irrelevant with modern brass and powders, correct? The actions are more than durable enough to take 50ksi, it's the brass thats the limiting factor. So the old adage of the Gibbs being a low pressure round is moot today? I could be wrong, anyone please chime in.

 

[Green Chile]

At this level, brass is NOT the limiting factor…your body is the limit. Also, no one can hold that kind of recoil to accurate levels. Experiment if you want to find your limits but 2100-2200 is the magic. You can learn to shoot that level well from field positions.

 

[mchammah28]

At this level, brass is NOT the limiting factor…your body is the limit. Also, no one can hold that kind of recoil to accurate levels. Experiment if you want to find your limits but 2100-2200 is the magic. You can learn to shoot that level well from field positions.

Good point. I'd be happy to push a 600g bullet to 2250fps. That's an accomplishment to be able to shoot reliably well.

 

[TSIBINDI]

...Starter load in my GMA Gibbs:

Jamison brass
Fed 215 primers
108gr R-15
Add 1/2" foam filler
Woodleigh 600gr FMJ

Velocity five shots across the screens averaged 2150fps. This load is mild enough that it won't leave you "Shell-shocked."

 

[RAVEN ROCKS PRECISION]

Congrats on your new rifle. Not sure if you saw the small sale we had on 505 Gibbs ammo, bullets, brass, and bullets the other day, but I just reactivated the coupon code if you (or anyone else) needs to stock up.

Norma Brass, Swift A-frame bullets, Norma loaded ammo, and new RCBS dies

Raven Rocks Precision

Raven Rocks Precision is an online store for all your shooting and reloading needs. We offer a wide selection of products, including rifle brass, projectiles, and hunting ammo.

ravenrocksprecision.com

Code: 505Gibbs

 

[Hunting Hitman]

...Starter load in my GMA Gibbs:

Jamison brass
Fed 215 primers
108gr R-15
Add 1/2" foam filler
Woodleigh 600gr FMJ

Velocity five shots across the screens averaged 2150fps. This load is mild enough that it won't leave you "Shell-shocked."

I have a similar load shooting 570gr Swift A-Frames at 2200fps. Deadly accurate and comfortable to shoot.

HH

 

[AZDAVE]

My 600gr load is right about where the other 2 gentleman have theirs. A 600gr at 2150-2200 will do everything you need it to. Try it at this level then you can decide if you want more and see where your shooting quality shots vs recoil raises its ugly head.

 

[Hunter-Habib]

120 grs Hodgson SC 4831, (SC = short cut) , Federal 215 Mag Primer, Norma Brass, DZOMBO brass 600Gr flat nosed monolithic solid.

This gave me 2140 fps with the 600Gr brass solid from a Joe Smithson Granite Mountain Arms African Magnum Mauser action .505 Gibbs caliber rifle’s 25.5" barrel - Should be fine for African summer temperatures, as well. No need for a filler with this load as the 600Gr bullets are long.