Yesssssssssssssssssssssssss! Macifej has kindly sent me a sample of his 505 Gibbs bullets to test.

Specs: 1.4695" to 1.4705" variance in length, weight went from a light of 558.7 grains to a heavy of 559.1 grains. They measure exactly .505" on the body bearing surface, and .474" in the five grooves/bearing bands. The meplat is .410" and the edge has a slight radius to "break" the meplat sharp edge. I expect that slight radius will make for flawless feeding in a fighting situation with DG. I just put a dummy round together, and seated in the crimp groove they are 3.788" OAL.

Tomorrow we will find out how they shoot and penetrate.

Rich
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Damn I was hoping it was a reamer

I am still happy for you though...

Results will be fun.

I hope the 505's perform as well as DHL!!! That was smokin' fast!!

I'll let you know tomorrow. Do you think a test of eight feet of stacked sand bags is a proper penetration test? I can do that in a 2x4 frame and set it up by myself. The bullets should take care of any thoughts/issues I would have taking it apart and putting it back in the Dodge! Home Depot to the rescue!
My gosh, but these are beautiful bullets!

Rich
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Whatever you think works! I know different guys who have this bullet will do different things to prove it's performance - so I'd say be creative. If your 650 grain 505 load is pushing 2600 fps then that's pretty hot for a 558 grain solid.

I might try nailing a shit load of 2x4's and/or plywood together in a fat wad and attaching it to the front of the sand bags. A piece of 1/4" steel plate would be interesting too if you could do it safely. Be careful of ricochets! I was once missed by a Garand launched ball round ricochet by a foot or so passed my head.

Sound like you guys are going to have a blast tomorrow! Too bad I won't be there to see the destruction.

I've always been curious as to how well drywall mud would be as a test medium. It has a good thick texture and a bucket weighs quite a bit. I think you would have to put it into a different type of container in case it blew it up like water in a 5 gallon oil bucket. I tried a small box of it with my 450 Ackley and you could see a rotational wave of mud flying through the air for about thirty feet each side of the target. I think I had it mixed to thin. If you laid the buckets end to end inside of a plywood box that you could lift the lid off it might work and be very consistent. You could put what ever else you wanted in front of the buckets or between them.
Take good care,
Dave

Did I say I love my CZ...? This rifle will take three 505 Gibbs loaded rounds with an oal of 3.86" and feed them perfectly.

Rich
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quote:

Originally posted by Idaho Sharpshooter:
Did I say I love my CZ...? This rifle will take three 505 Gibbs loaded rounds with an oal of 3.86" and feed them perfectly.

Rich
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Do tell Herr K!

Yah, seated them in between the front and second groove and put a light crimp on.

Rich
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El feed-o Rapido?!?! Any photos of the long load?

raining all dang day!

Rich
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What? You guys don't have a 100 Meter indoor range which allows large messy reactive targets!?

How is the MKII coming?

in a word, NO! And it's raining again. Drats!

Rich
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Do you live in a "Rain Forest" Rich??!

Check this ultimate shooting range. I paid them a visit last fall. Like Disneyland for shooters.

MANNLICHER Europa Schießzentrum

Cripes! We get 15-18 inches of rain a whole goshdarn year...and all of it the last five days I think!

I think I'll go load some more 416 Rigby and (obsolete) 375H&H ammunition and sulk for a while.

Rich
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Man! Those bullets are beautiful.

Mac,
I got mine. Will test as best I can, when I can, and get back to you. They are beauties, just as Rich says.

I'll load some and get a picture of how long I can make the nose.

magazine box length is the limiting factor.

I get up at six, go to our Men's Bible Study/Breakfast...look out the window at seven am and it's snowing! Not getting any good karma here folks.

Rich
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I'd say that should be expected on the 46th parallel at 2700 ASL in November.

tomorrow...if it dries out just a little!

Rich
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I loaded some to try too. 120 to 135 grains of H4831 for starters. There is still a little powder "shake room" in the case even with 135 grains of H4831.

Ridiculous as it sounds, CZ placed a rubber pad inside the front of the box on those first .505 Gibbs they sent out. This was to cushion the nose battering under recoil I suppose. Ridiculous!

Subsequently they went to just a thicker steel reinforcement of the front of the .505 Gibbs box, which gives more room than the rubber padded one.

I peeled that rubber pad out of the front of the box on my "first edition" model and gained some nose room. I can load them out to 3.925" and it cured the left side feeding problem. Good nose shape in my rifle now. of course now I need to reinforce the front of my box with a little rectangle of steel or just steelbed right up against the outside front of the box, and polish the surface where the rubber was glued inside the box. Kansas City Rube Goldbergs!
Hey, it is a shop mule. I'll just feed one round at a time off the top of the box until I get the box reinforced.

Here is how the S&H bullets look crimped in the middle of the second groove (3.925") and crimped tight up against the start of the first groove (3.813"). CIP max COL is 3.830", and the CIP throat is just a leade with zero freebore. It worked out perfectly. The CZ does not have a CIP minimum throat, but he S&H .505 Gibbs 558-grain brass FN solid will fit a CIP minimum throat just fine, as planned:

THANK YOU RIP!!!!!!

I loaded a dummy and ran it into the chamber. My loads look like the one on the left. The sun is shining, and I am headed out. 120,125, and 130gr of AA3100, pretty close to your loads.

Thanks for posting the rounds.

Rich
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RIP - Thanks for your photos and data.

ISS - Thanks for braving the sloppy weather to test.

TSBindi - Thanks for doing the high altitude alpine Gibbs load development. The Snow Dumbo is a dangerous beast indeed!

Anyone else who has a 505 is welcome to join the party!

Data, photos to Macifej to follow...

36-degrees! Bright sunny day, no wind. Test media: wet sand in bags, 3/4" plywood spacers between 16" of sand per bag.

120gr AA3100......................1981fps avg, penetrated 16" of sand and two of three stuck base in plywood, did penetrate. Weight unfired: 559, recovered:554.5/553.4/554.0gr

125gr AA3100......................2063fps avg, penetrated first bag and plywood, 6-7" into second bag.
23-24" of sand and one layer of plywood, recovered weight: 551.5/554.9/554.6

130gr AA3100......................2203fps avg, penetrated first bag and plywood, second bag and plywood, 2-3" of
penetration into third bag of sand, 35-37" if sand, recovered weight: 552.4/552.6/550.4gr

Unfired bullets mike very consistent at .5042-.5046". Length varies from 1.469-1.470. .5gr weight variation in 40 bullets, less than .002" length variation. All fired bullets retained 99+% weight and length.

I would ask anybody here with a .505 Gibbs who reloads to please "mike" their expander button and post it here. I have CH4D dies and my button is .5045".

It works about perfect with my cast gas-checked 650gr bullets, they mike .5055", but it needs to be about .001" smaller for these Big Macs.

In a day or three we'll get some fired with the VV0y 165.

regards to all, and have a happy Turkey Day!

Rich
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Rich,
Holy Cow! 3 feet of sand bag and two plywood boards of what thickness? Sandbags are very tough bullet stoppers.

And a steady progression of penetration with velocity.

I don't suppose the nose deformed at all?

Your loads were AA-3100, right between IMR-4831 and H4831. All very close to same burn rate. My velocities should be very close to yours.

You have done all the penetration testing needed there. The rest is gravy. I will just see if I can get into the 2300 to 2400 fps range, no higher, use a scope and see if I can make tiny groups with the S&H bullet.

From your data:
1981fps/120gr >>> 2063fps/125gr: 16.4 fps/gr
2063fps/125gr >>> 2203fps/130gr: 28.0 fps/gr
overall:
1981fps/120gr >>> 2203fps/130gr: 22.2 fps/gr

If about 100 fps per 5 grains added:
135 grains >>> 2300 fps
140 grains >>> 2400 fps

I hear that Ryan Breeding's max .505 Gibbs load with a 600-grain RNSP bullet is 144 grains of H4831 for 2500 fps, barrel length unspecified.
140-grains of H4831 with the 558-grain S&H bullet ought to be do-able. An accurate load in the 2300 to 2400 fps ballpark should be great, IMHO.

Barrel length of your CZ?

Mine is exactly 24" from muzzle crown to boltface, measured by a cleaning rod in the barrel.

Oh yeh, expander button on the decapping and sizing die in my RCBS set: 0.336" diameter, it looks something meant for a .338.

Mine is a 3-die set with the extra die to expand the neck and bell the case mouth in a separate step. That neck expander measures just about .5045" by my eyeball between the .001" graduations. I only expand about half the length of the neck and no belling required before I seat the S&H bullets, and the RCBS dies do provide all the "death crimp" necessary.

Rich,
How about adding ".505 Gibbs" somewhere in the title of this thread? You can do that by editing your opening post of this thread.

That might attract more .505 Gibbs reloaders to input this thread.

3/4" plywood. My barrel is 24" long. I am going to see what 140gr at least, of AA3100 will clock. I am really liking the V V oY powders.

Take care,

Rich
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Excellent work Guys!!

Monster penetration indeed! Will be very interesting to see the max velocity penetration tests.

Rich if you e-mail your photos to me I will post them here.

Curious that your mic'd diameters varied so much. When we did random sampling during production with calibrated test equipment in the shop - the total variance of the lot was .50495" +/- .000005. not that it matters but I will look into any potential variances greater than machine deviations.

Your mileage may vary.

Awesome 3 feet of penetration in wet sand bags is pretty good

Macifej,

Again nice bullets with spectacular turnaround!

It is wonderful to see people here on AR work together on projects and the results of their efforts

John

I measured 5 bullets.
All 5 are 1.469" +/- .001" in length, and I really can't measure any better than .001" with certainty.

All 5 were exactly .505" to my limited ability to measure.

Weights of 5 bullets in grains by digital scale:
558.4
558.6
558.3
558.1
558.4

That's all I need to know about their uniformity.
Material must be very consistent composition too.

137.5 grains of H4831 is a 100% load: no powder shake, no drop tube used.

140.0 grains of same is barely compressed.

Some 100-yard 3-shot groups with a scope for accuracy screening coming up, 3-shots each with:
120.0
125.0
130.0
132.5
135.0
137.5
140.0
grains of H4831.

Beautiful!!

Hey if one of you guys could get a really good High Res photo of things like a round on the follower, fired bullet, loaded round short, etc I will post them in a new 505 section on my site with attributes. Of course photos of awe inspiring destruction are useful as well. AND maybe load data for an upcoming S&H Manual of various exotic calibers in action.

Wait till you guys see the new .395 Elk Grenade bullet coming up!!

HOLY SHEEEEET!!! That thing is crazy!! Glad I'm not a Colorado Elk!

That is a really interesting set of postings! Does anyone have a load for H4831 and 600gn bullets for 2200fps. I have a 505 Gibbs built on a Granite Mountian Arms action, and I can't find much data for 600gn loads.

I think you will find AA3100 and H/IMR4831 so close in burn rate that the difference in velocity or pressure is inconsequential. I would suggest that 130 grains would get you there. Check back in a week, I should have more data posted about Tuesday.

Rich
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Macifej,

How about you cook up some of these in 416 for the Rigby owners? Nice looking bullet design.

TG

Thanks Rich, Much appreciated.

quote:

Originally posted by TMG:
Macifej,

How about you cook up some of these in 416 for the Rigby owners? Nice looking bullet design.

TG

Todd,

In a few weeks I will have .375, .395, .416, .458, .505, & 550. There are already two flavors of 395 & the 505 you see here in the field. I'm also producing some copper free cleaning jags for these calibers. I got drafted into doing work on a case/bullet/rifle design for a customer so these guys are a bit delayed but should have them done and ready to ship mid December.

How's your 10.75 x 68 working out?

It got sidetracked into a 404 Jeffery, but may end up back to a 10.75 x 68. My mag box is dimensioned for the 10.75 but [now] long enough for the 404.

Then inspiration struck: load the 10.75 to longer OAL and use up the extra space! Of course the OAL is longer anyway when you use a 400 gr. bullet instead of the 350 or whatever it is in original Kynoch ammo.

quote:

WOW those bullets looks great.
Interesting project.

Cheers,

André

Just as an aside, Macifej has been excellent in his help with the .395 caliber. A really decent guy to work with who listens to your suggestions and doesn't make fun of your errors in thinking (like I have made).