Okay, took the 475 NE out to the range yesterday. Very nice 'Spring' day here in the Willamette Valley.

Anyway I'm still trying to dial in a load that shoots to regulation. Tried R15 again with 4 gns of dacron. Started an 86 grns and went up to 90 in .5 increments. The 86 loads were doing about 2000 fps and they moved up to right at 2100 at 90.

The right barrel was shooting high (2 in) and to the right (4 in) (of POA) and the left was shooting low (2 in) and left (4in). Both barrels were about equidistant from the POA, albiet in opposite rectangular coordinates. As I progessivly shot hotter loads, the right barrel came to the left, eventually ending up directly above POA by two inches.

The left barrel never did come in. It eventually came up about to horizontal with the POA, but is was still shooting left.

I got the feeling that if I kept things up they both might have come together. However the reference materials say that the speed of factory ammo is 2175, but with a 28in barrel. My barrel is slighly longer than 25in.

Question: Can I come up a bit more on the loads to see if they'll come in? If so how far?

Additionally I got a few rounds that were not shooting as fast as others in the load group. Impact points reflected this as well. All loads were weighed on a digital RCBS scale. Should I up the amount of dacron another 0.5-1.0 grns to get more consistant loads?

Everything was done at 50 yrds.

Another question; I'm thinking of trying IMR4831 to see how it does. In Wright's book he lists 96grns for the 475 NE. However using his 1.33 mutliple for 75grns of cordite, I get 99.75. If I start at 96, I'm feeling that I'll end up with too much space above the powder. So I started out at 98 and worked up to 100 in .5 grn increments. I still have a bit of space above the powder (about 3/8 in). Does this sound okay or should I start lower?

Thanks for putting up with my questions on this!

-Steve

Hi Steve,
Get me up to speed on your double rifle, please.

Is this a 475 NE 3-1/4" which uses a .483-caliber bullet of 480-grains in a straight walled case, no bottle neck?

Surely we can get the experts to work on this soon.

I am well versed in the 470 NE loads, but that is a slightly bigger case, with .475/500gr bullet, if I have your cartridge pegged.

I went up to 92 grains of RL-15 with foam filler, and 90 grains with Dacron filler, though the traditional loads for the 470 NE were said to be 87 to 89 grains.

Powder lots may vary, and brass may vary, so the chronograph and rifle performance rule.

I ended up being most satisfied with the H4831 Extreme powders whether long cut or short cut.

They will certainly fill your case better, especially the long cut. You will get lower pressures for sure, but the pressure peak will come with the bullet slightly farther along the barrel, if this is for an antique rifle.

In My Merkel, 108 to 110 grains works, depending on the bullet. No filler needed.

If you have 3/8" of air space in the case above the IMR831, sounds like some Dacron is needed there.

Have you measured the water capacity of your cases?

Is the 475 NE just like a 450 NE 3-1/4" necked up to .483 caliber?

Should be interesting to see what the experts
say.

MacD37?

400 NE?

Graeme Wright load data does not jive with my powders.

475 NE with .483/480gr bullet:
96 grains of IMR-4831/ 2080 fps

470 NE with .475/500gr bullet:
105 grains of IMR-4831/ 2060 fps
103 grains of AR 2213 (H4831)/ 2100 fps
121 grains of AR 2214 (H1000?)/ 2100 fps
85 grains of RL-15/ 2125 fps

Yes indeed, powder lots and brass cases, and even the bullets may change over the years, making any application of Wrights recipes open to adjustment.

Your rifle seems to be getting closer to spot on.
Certainly no need for re-regulation so far.

I say keep adding the powder until they come close to converging at 50 yards, then back off. Pretty close now, eh? Maybe time to split the differences between the barrels with a sight adjustment when you get the convergence you want in the horizontal plane.

Another thing:

Yes, before going up on the powder charge, add more Dacron.

Pack it tight.

I found that 5 grains of Dacron in the 470 NE gave slightly higher velocities with the same load of powder as compared to a 2 grain disc of the polyurethane foam, that was about 5/8" thick and 1/2" diameter, cut with a 50 BMG case with a sharp chamfer, cookie cutter style.

The tightly packed Dacron stuffing is denser and a better "air-eliminator" than foam.

I will not use foam anymore. I will use Dacron with RL-15, but my H4831 loads with no filler are my favorites in a Merkel.

And use a Dacron filler with the IMR-4831, if you have that much air space.

Didn't JudgeG have a 475?

Rip,

Thanks for the advise!

You are correct about the cartridge. 3 1/4 straight walled, 400 grn., .483 inch.

I haven't measured case capacity, but I will do so and get back to you.

Can't tell you about the origins of the cartridge itself. I'm a newby ...

I'll try the 4831 with a bit of dacron.

How far should I 'push' the measured velocity against the published numbers? As the published numbers that I have were done in a bit longer gun, I'd think that I should keep them down a bit from the top.

Forecast is for rain for the next few days. Demo period is over here in the PNW. Might break later in the week and if it does, I'll get back out and try 'er again.

-Steve

Steve,
Sounds like about 2100 to 2150 fps max is as far as you should consider going. Anywhere in that ballpark should do.

What make of brass do you have?

Rip,

H&H nrass.

-Steve

quote:

Originally posted by 400 Nitro Express:
[QUOTE]Originally posted by Steve:
How far should I 'push' the measured velocity against the published numbers?

Don't.

It would be nice to find some original Kynoch (Cordite) to chronograph in your rifle for a baseline, but that probably isn't possible. The .475 3 1/4" was one of the first to be dropped after WWII, so it is very hard to find. Given a standard velocity of 2175 in 28" barrels, if your rifle has 25" barrels, I wouldn't push it much beyond 2100 fps.

I agree with RIP entirely. Each rifle is different and there are lots of variables. Density variance between lots of the same powder can make a BIG difference. I view the "conversion" factors for RL15 and IMR4831 from Cordite as rough guides to maximum loads, not starting loads. There's too much difference between powder lots to treat them any other way.

As an example. The .500/.465 is also a 75 Cordite/480 bullet cartridge as is your .475, based on the .500 basic case instead of the .450 basic of your .475. Standard velocity is 2150 fps in 28" barrels. I just got finished working up for a Holland .465 with 26" barrels. Late run Cordite factory ammo ran 2100 fps even. I started at 84 RL15 with 480 grain Woodleigh softs and Kynoch wads (at the owner's request) and worked up in 1 grain increments to 87 grains. 87 grains gave 2150 fps (too fast) and crossed, 86 gave 2100 fps for perfect regulation, and was the final load.

The "standard" conversion from Cordite to RL15 is 119% or 89.25 grains. With that particular batch of powder in that particular .465....ain't no way in hell. You have to let the rifle tell you what it wants - up to a point. Absent a pressure gun, standard velocity, as adjusted for barrel length, is the only guide that you have. If a given combination of components won't regulate at that velocity, try something else.

As RIP suggested, increase the dacron a bit. If that doesn't work, try 4831, but start low and shoot over the chronograph. In the rifles I've used it in, I've never been able to reach the conversion amount with it either.
----------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

400,

Thanks for the advice. I really appreciate it. I'll try what you and Rip have suggested. If the rain holds off I’ll try to get to the range tomorrow or Thursday

-Steve

Okay, here's the latest. Took it out yesterday afternoon. Nice day and an excuse to blow out of work early.

Shot a few more R15 loads that were basicly the same as before. I already had them loaded and I wanted to reverify everthing. The left barrel was actually shooting farther to the left than I originally reported. Closer to 6" than the original 4" I said before. I stopped when I got close to 2130fps.

I then tried some IMR4831 at 99, 99.5 and 100, no filler. Was getting 1800-1880 fps. But impact points were very similar to the top end of the R15 loads. So I think that I'm going to try H4831 (w filler on the lower loads) and see what happens. I think that it might get closer to regulation as I work things up. We'll see.

I also shot some of the original 3031 loads that came with the gun. They were also shooting in the 1800's. I'm going to pull some bullets and verify powder weights.


-Steve

Steve,
Have you contacted Al about what he was loading the Coggie with?

Doc,

Yes, I've talked to Al. 71 gns of 3130 with 2 gns of dacron. I've also got some rounds the he loaded. I'm not able to get them to shoot to regulation either. Those are the ones that I mentioned that came with the gun in my previous post. They were only chronoing in the 1800's

I'll pull a bullet or two from some of them and double check the weights.

I'm certainly not above thinking that it's something that I'm doing...

-Steve

Steve,

Is the gun in contact with anything when you are shooting? I like to rest my left hand on a sandbag, but no part of the rifle touches the bags or anything else except for my shoulder, grip/trigger finger and my left hand. Also, my left hand does not hold the forearm like when shooting a bolt rifle. Instead, the forearm sits in my left palm, and my thumb and fingers wrap up and around the barrels.

Dan,

That's pretty much how I 'think' I'm holding it. The sand bags that I'm using as a rest are stacked relatively high to get me sitting as upright as possible. Left had on the bags holding the fore-end. Fingers wrapped around the barrels, firm, but not a death grip. Elbows resting on the bench. Stock pulled squarely into my shoulder and cheek. I haven't noticed anything on the rifle touching anything but me.

You'r thoughts got me thinking. Maybe, I'll try a couple of shots standing and a couple more off sticks (hand holding the rifle, not the sticks themselves). This might give me an indication as to whether it's my form on the bench.

Thanks!

-Steve

Steve:

Just to remove any variables, has anyone else shot that rifle with the loads you mentioned? If so, were their patterns consistent with what you were getting?

I don't post this to insult your shooting ability, but each shooter is different. Load work up for the big guns, with iron sights, off hand/on sticks/shooting from the bench without a rest isn't as easy using a rest from a bench.

Good luck with your development.

quote:

Originally posted by 577NitroExpress:
Steve:

Just to remove any variables, has anyone else shot that rifle with the loads you mentioned? If so, were their patterns consistent with what you were getting?

I don't post this to insult your shooting ability, but each shooter is different. Load work up for the big guns, with iron sights, off hand/on sticks/shooting from the bench without a rest isn't as easy using a rest from a bench.

Good luck with your development.

577NitroExpress,

There's no way you could insult my shooting ability! There is a guy at the club that owns a 475 Jeffry that I've also been talking too. I'll see if I can get him to shoot it as a verifcation. Good suggestion.

BTW guys, I really appriciate all the suggestions and help.

-Steve

Steve

Another thought - what temperatures were you shooting in? While I doubt it is not going to throw off a 300 fps difference in velocity, I would guess that Al's loads were developed to function in Texas temps. 71 grains at 95 degrees is going to be faster than 71 grains at 30 degrees. There is going to be some difference there.

Your chrony is going to be your best friend for awhile

Jim,

I've been as careful of temps as one can this time of year. I've been shooting in 50-60 degree weather.

The 71 gns.loads that he sent me (and I verified the weights last night) were actually his 'cold weather' loads. His regular load is 70 gns.

-Steve

Eliminate that one as a variable.

Is your rifle a 483 or 488? And this is a 475 or a 475#2?

I can play around with the Quick Load program and see what I get.

I tried Quickload for a 475 #2 - shows 94 graind of RL 15 gets you 2103 fps using a 500 grain 488 caliber Woodleigh FMJ out of a 25 inch barrel. At that load, pressure reading goes to yellow (a caution) estimnated to be 30,733 PSI and 2119 BAR.

I just received the new Quickload program, which is different (in a better way) than the old one. Still trying to figure out how to navigate.

Jim,

It's .483", 475 Nitro. Not the #2. I was getting right around 2100 @ 90 gns. 480 grn Woodleigh SP.

Thanks!!

-Steve

Steve,
If you didn't do this before purchasing, give it a go:

Disassemble the rifle.
Hang the barrels in the air by a loop of twine around one of the lumps.
Whack the barrels with a rubber mallet.

Is there a pleasing tone heard?

Hopefully no rattle or buzz.

If all is harmonious, proceed with load trials and shooting technique refinement.

If your barrels make bad music ...

Well, the Quickload Program has every other 475 except the 483 NE. Has something called a 475 straight NE, but matches it up with a 474 bullet.