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#11963565 - 04/10/17 Re: 505 Gibbs modern powders. [Re: 416RigbyHunter]
416RigbyHunter Offline
Member

Registered: 02/08/09
Posts: 198
Hi all,
OK, just a quick update, I have settled on 148gr of Retumbo with the 600gr Woodleigh PP, am yet to get my hands on some solids in that weight.
Unfortunately, my chrony stopped working at 146gr, one round at that weight registered 2284fps, I then proceeded to 148gr but the chrony didn't register any of the 3 shots.
I was a little taken aback, the velocities with this powder were quite a bit slower than I expected, the 140gr load only registered 1804fps! The primers were also backed out and rounded.
The recoil at 148gr is stiffer than I would like, but the rifle groups so well at this powder weight/velocity.

Thanks again to all those that helped me out, your info was invaluable to me getting this thing shooting right.

Cheers.

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RV 728 BP
#11963652 - 04/10/17 Re: 505 Gibbs modern powders. [Re: 416RigbyHunter]
Dirtfarmer Online   content
Campfire Kahuna

Registered: 11/28/10
Posts: 19316
Loc: Central Louisiana
Buddy I grew up with is leaving for Zim, end of May, going after Cape Buff. He's shooting his Ruger 77, .416 Rigby, full house off hand at a hundred. He's putting most bullets in a 6" bull, the others, pretty darn close. He'll keep practicing until he leaves. He should do well.

Even as a youngster, he was known to be quite a marksman. Once a neighborhood dog came up crippled, had been shot. The owners accused this young lad of shooting their dog. Lady across the street let them know this boy didn't shoot their dog. Asked how she knew, she replied, if this boy shot your dog, it'd be dead... shocked

Sorta sums him up... cool

DF

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#11976760 - 04/17/17 Re: 505 Gibbs modern powders. [Re: Dirtfarmer]
416RigbyHunter Offline
Member

Registered: 02/08/09
Posts: 198
Hey all,
I measured my twist in this rifle, 5 passes told me that it has a 1:10.25" twist rate.

Do you think this fast twist could be causing my low velocities with Retumbo, or is it something unrelated?

I don't recall being asked what twist rate I wanted when I ordered this rifle, just that it was cut rifled and rust blued.

Cheers.

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#11976813 - 04/17/17 Re: 505 Gibbs modern powders. [Re: 416RigbyHunter]
jwp475 Offline
Campfire Kahuna

Registered: 04/25/05
Posts: 20852
Loc: USA
Originally Posted By 416RigbyHunter
Hey all,
I measured my twist in this rifle, 5 passes told me that it has a 1:10.25" twist rate.

Do you think this fast twist could be causing my low velocities with Retumbo, or is it something unrelated?

I don't recall being asked what twist rate I wanted when I ordered this rifle, just that it was cut rifled and rust blued.

Cheers.


Twist rate will not affect velocity, that is a repeated false hood. I have a friend that works in a ballistics lab and they have tested the same load from a 14 twist to a 7 twist and it doesn't influence pressure or speed.
_________________________

I got banned on another web site for a debate that happened on this site. That's a first

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#11976834 - 04/17/17 Re: 505 Gibbs modern powders. [Re: 416RigbyHunter]
gunner500 Offline
Campfire Oracle

Registered: 09/08/09
Posts: 29165
Loc: Oklahoma
Originally Posted By 416RigbyHunter
Hey all,
I measured my twist in this rifle, 5 passes told me that it has a 1:10.25" twist rate.

Do you think this fast twist could be causing my low velocities with Retumbo, or is it something unrelated?

I don't recall being asked what twist rate I wanted when I ordered this rifle, just that it was cut rifled and rust blued.

Cheers.


416,

I need my ass kicked for quoting my load info [WITHOUT] referencing my load book, my 505 Gibbs loads are made up using H-4831 short cut powder, not Retumbo.

If you'll substitute Retumbo with H-4831 the speeds you seek will be there.

Very sorry for the fu-k up. mad

Gunner
_________________________
"One Eye Is Taken For An Eye"

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#11980803 - 04/18/17 Re: 505 Gibbs modern powders. [Re: gunner500]
416RigbyHunter Offline
Member

Registered: 02/08/09
Posts: 198
Thanks Gunner, no problem with your mistake.
H4831sc is the only powder I haven't tried.
H1000 was very promising, but I ran out of it just after load testing.
RE22 is another good one, but recoil is sharp and not pleasant for me, even with a shooting pad on.
I fired 6 rounds last Thursday trying to get good chrony info @ 148gr of Retumbo and my chrony just doesn't like this cartridge, I kept getting error2 readings, then the final shot registered 2100fps, almost 200fps slower than the last velocity reading with 146gr. I am confused!

Anyways, I will persist with it, I have a big bore shoot this coming weekend and will use up what rounds I have left for it.

Cheers.

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#11981167 - 04/18/17 Re: 505 Gibbs modern powders. [Re: 416RigbyHunter]
gunner500 Offline
Campfire Oracle

Registered: 09/08/09
Posts: 29165
Loc: Oklahoma
416RH, Thanks just the same, but i messed up big time, I safely ran those 600 gr Woodleighs upwards of 2465 fps with the H-4831 powder, no over pressure problems at all in my rifle.

My loads now run 2150 fps, I gotta believe that's plenty for any game animal worldwide, my 505 is relegated to the excellent iron sights that came on the gun, I'll only use it for very big animals up close, it has killed two scoped in the past.

Your chrono is most likely giving you fits from the massive gas wave from burning 145+ grains of powder, I chronoed my 505 from 25' back, works just fine, make sure your not shooting next to a structure, or under a low roof, the gas has nowhere to go but straight into the machine if confined, also check that you have a good hot battery too.

Gunner
_________________________
"One Eye Is Taken For An Eye"

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#11981335 - 04/19/17 Re: 505 Gibbs modern powders. [Re: gunner500]
416RigbyHunter Offline
Member

Registered: 02/08/09
Posts: 198
Gunner,
I got 2550fps with H4350 and those 600gr Woodleighs, but the recoil is way past my threshold. I would have to practice every day at that level and I doubt I would ever get accustomed to it.
I was happy at 2300fps, so I assume it's my chrony that's giving false info.

The battery was brand new 2 tests ago, so it should still be highly charged.
I will test again this weekend and see how I go.
I would like to re-test H1000, as the recoil was tolerable. This rifle kicks much more than my double in 500 Nitro, but it does only weigh just over 9.5 lbs with mercury recoil reducer installed. It's a bit light for me I think.

Cheers.
smile

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#11986591 - 04/21/17 Re: 505 Gibbs modern powders. [Re: 416RigbyHunter]
gunner500 Offline
Campfire Oracle

Registered: 09/08/09
Posts: 29165
Loc: Oklahoma
Okay, I see, thought you were never able to get the speeds you wanted, thought it was due to my bogus Retumbo load data. crazy grin
_________________________
"One Eye Is Taken For An Eye"

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