Just received a 450/400 NE 3" that I had built on a J.P. Sauer SxS 12ga shotgun, and ran across an issue that I'm not sure how to go about having corrected.

I have 10rnds of live Hornady ammo left over from a previous 450/500 NE 3" and 80 or so brand new Hornady 450/400 NE 3" brass. Went to shoot the gun tonight just to see how it handled. Of the 10rnds, I was only able to completely close the gun on 4 rnds. By completely close, I mean, top lever back to center or just right of center, and the Greener cross-bolt flush with the receiver.
Took some initial measurements of the brass rim thickness. Cases with a rim thickness of .058" or less allow complete closure and lock-up of the action. Thicker rimmed cases do not allow full closure and lock-up. Measured pretty much every case - loaded and unprimed new brass that I have. Rim thickness falls between .057" and .062". From what I can tell the case rim thickness should be .065" from the case drawing I was able to locate. I could understand having an issue if the rim thickness of the brass I have exceeded .065" but it doesn't. This issue does not bode well with me and not sure how to go about correcting it. The gun closes and locks up tight when the chambers are empty - every time.

http://www.loaddata.com/member....cfm?MetallicID=5750

What's the next step?

I had a similar issue with my 500 NE. What I found was as follows:

1- Some of the ammo was out of tolerance. Hornady replaced the ammo.

2- After the ammo didn't cure the problem. I started looking at the gun. I am not certain of the correct technical terms. My description is that one chamber was not cut as deep as the other.

No problems at all now.

When I got my 100 y/o 450-400, JJ Perodeau fitted a new extractor. I found that the gun would not close on some brass (he must have used test rounds with thinner rims). I had another gunsmith make tiny cuts in the extractor until the gun would close on all my brass, which was Bell & Hornady. Possible it's the extractors and not the depth of the rim cut in the chambers? I sure wanted to make sure it would close fully on any round I put in the chambers. Would not want to fire the gun when it was not completely locked up! Bob

I have had some the same experiences with Hornady ammo, although upon calling them directly they said it was in spec...the differences in rim thickness in one box had a range of .008" difference. The oversized rims were above SAMMI specs, so if you reamed the chamber deep enough to allow them to chamber the undersized cases would then have enough room to expand a substantial amount, drastically reducing case life and or splitting.

quote:

a range of .008" difference.

That is a very very small amount.

.008 difference and above SAAMI specs are two
different things.

Bell, Bertram would be the same as above
or more.

Name me a maker that can make rim thicknesses
more equal than that ????????

I have the same problem with my 450/400 3.25- Hornady, Jamison and Bertram- all with variability of rim thicknesses. Get a mini lathe and clean up the inner face of the rim to bring into your rifles spec. See the discussion in G. Wright book pgs. 32-34.

Guns in the 60's - 80's were modified in Aust
to take Thick rim cases as these were all
that were available.

quote:

Name me a maker that can make rim thicknesses
more equal than that ????????

I have a cheap box of S&B that has a variance of .002".

As an after thought and prior to reading the follow-ups here, I did remove the extractor to see if that was causing an issue. No change.

I did call Hornady and talk to the tech support folks there. hey sent me a drawing and spec sheet that shows .052" to .065" as allowable measurements for rim thickness on the 450/400 NE 3". They told me they try to hold rim thickness to .057/.058" - .062".

Spoke to the gentleman that built the rifle for me and he measured the brass he used for regulating (Hornady). He said it was from an early lot and measured .052"-.053". He's sending me his reamer and gauges (overnight) so I'll see where it's at when they arrive, and possibly hand ream the chambers.

When I had my issues, I learned that Hornady had some ammo that was labeled "regulating". It was always right dead center in the spec range. However, the ammo not marked as such is where the problem was.

Updates:

1) I did check to see whether the extractor itself or the cut in it may have been causing an issue. Simply removed the extractor and tried to chamber some of the brass that I had and was giving me problems. Removing the extractor did not resolve the issue.

2) Measured and remeasured the rim cut in each barrel. .058" was the number I came up with virtually every time on both chambers.

3) Contacted the builder and he ended up overnighting his reamer. Also got a hold of a 450/400 go-gage. Rim thickness measured .065". When the reamer arrived I reamed each barrel so that the action would just close on go-gage. Measured each barrel along the way as I reamed them. Slow process by hand, but it needed to be done that way.

After I got done reaming the barrel, I cleaned the chambers and barrels and then proceeded to check EVERY round - loaded, new unprimed brass and sized brass - to make sure that the action would close properly. This too was a bit of tedium as I have lots of brass.

Now, or should I say when the humidity drops, it'll be off to the range to do some shooting.

Interesting note about the 450/400 gage. It is unlike any other that I have. 1) It's short, and 2) it has a significant under-cut between the rim and the rest of the gage. Found that in order to make a check with the gage, it had to be done with the forend off so as not to activate or elevate the extractor. With the extractor elevated the gage could easily slip over or past the extractor.

quote:

Originally posted by 2Barrels:
Just received a 450/400 NE 3" that I had built on a J.P. Sauer SxS 12ga shotgun, and ran across an issue that I'm not sure how to go about having corrected.

I have 10rnds of live Hornady ammo left over from a previous 450/500 NE 3"
Went to shoot the gun tonight just to see how it handled. Of the 10rnds, I was only able to completely close the gun on 4 rnds. By completely close, I mean, top lever back to center or just right of center, and the Greener cross-bolt flush with the receiver.

With the old rounds for another rifle, if they are hand-loads, it could be that you resized the brass by neck sizing only, and the chamber in your older rifle may have had a little longer chamber than the new one. This may not be the rim thickness at all, but simply fire formed in a different chamber. To check the rim thickness you need to take the barrels off the action and stand the barrel set muzzle down, then place the rim of the cartridge in the chamber primer first and see if brass shows above the surface of the barrels, and try each cartridge in both barrels. This will tell you if you have one tight rim cut in the barrel set, or if the case shoulder may be the problem.

quote:

and 80 or so brand new Hornady 450/400 NE 3" brass.



Took some initial measurements of the brass rim thickness. Cases with a rim thickness of .058" or less allow complete closure and lock-up of the action. Thicker rimmed cases do not allow full closure and lock-up. Measured pretty much every case - loaded and unprimed new brass that I have. Rim thickness falls between .057" and .062". From what I can tell the case rim thickness should be .065" from the case drawing I was able to locate. I could understand having an issue if the rim thickness of the brass I have exceeded .065" but it doesn't. This issue does not bode well with me and not sure how to go about correcting it. The gun closes and locks up tight when the chambers are empty - every time. What's the next step?

The rim cut in the barrels should be .066, or .067 so it will take all ammo and close on a .065 rim. If the .065 rim will not let the rifle close, and the shoulder is not the problem, then the smith needs to relieve the rim cut depth to .066, or .067! .002 over is not enough to hinder the pin reaching the primer, but allows room for a variety of ammo.

Good luck, and let us know what you find!



OOPS! Just read your last post, and it seems I was too late! I guess it pays to read more and post less! ................SORRY!

Since rimmed ammo headspaces on the rim, the ammo rim thickness and the chamber should be as close as possible. Over-sized chambers create a excessive head space problem, increases felt recoil, and is tough on the gun.

quote:

Originally posted by Kebco:
Since rimmed ammo headspaces on the rim, the ammo rim thickness and the chamber should be as close as possible. Over-sized chambers create a excessive head space problem, increases felt recoil, and is tough on the gun.

The above is absolutely true! However many of the vintage doubles chambered for the same round will have slightly different chambers depending on who's ammo they were regulated with. So if the loaded ammo was loaded for a vintage rifle and when the brass is reloaded it is only neck sized it may not work well in another double rifle, especially a new one. The ammo made in the late 1890s, or early 1900s by one ammo maker was not that well matched to other makes of ammo. Even today this thread has proved it is not that exact today either!

On the flange head space, the .002 (two 10,000nds) over is not a sloppy headspace and will not be perceptible by the shooter or the rifle.

.....................................................................

There are a few doubles out there that have had their chambers cleaned up due to pitting or rusting. If the gunsmith doesn't know what he is doing, it can turn out that a case fired in one chamber and only neck sized may not chamber in the other chamber. I have seen two doubles where one of the chamber had fired cases visably larger than the other chamber.

465H&H

quote:

Originally posted by MacD37:

I have 10rnds of live Hornady ammo left over from a previous 450/500 NE 3"

quote:

With the old rounds for another rifle, if they are hand-loads, it could be that you resized the brass by neck sizing only, and the chamber in your older rifle may have had a little longer chamber than the new one. This may not be the rim thickness at all, but simply fire formed in a different chamber. To check the rim thickness you need to take the barrels off the action and stand the barrel set muzzle down, then place the rim of the cartridge in the chamber primer first and see if brass shows above the surface of the barrels, and try each cartridge in both barrels. This will tell you if you have one tight rim cut in the barrel set, or if the case shoulder may be the problem.

quote:

OOPS! Just read your last post, and it seems I was too late! I guess it pays to read more and post less! ................SORRY!

No problem Mac. This was a learning experience for me.

The 'previous 450/400' I referred to was a Sabatti . The remaining live rounds are Hornady factory 450/400 NE 3".

I'll have the DR conversion out on the range this weekend for some shooting fun and longer test drive. With the chambers/rims reamed to .065", I tested every 450/400 round of ammo and brass I own and am confident that each will chamber in the gun.

The question that keeps churning in the back of my mind is "how many rounds of 'undersize brass' did the builder have and is the gun truly regulated?" Guess I'll find out the answer to the latter this weekend.