I have been told that it is OK to use .411 bullets in a 450-400 with a bore of .410. Is this correct and safe? Given the recent threads on the use of Barnes bullets in DRs the use of the larger bullets would seem to potentially cause the same problems.

Yes, no problems.

HOWEVER, you need to make sure that the bore has been measured correctly from the lead slug.

2 possible problems:-
1. The lead slug has not been hammered enough to
fully engage the rifling all around before being hammered through the barrel (it's normally obvious)

2. English guns often have uneven rifling SO,
when measuring the bore diameter from the lead slug, you need to make sure you measure from the edge of a groove to the other edge.

I hope you can understand that.

Now, before the US starting requesting Woodleigh make .408 bullets, everyone was using .411 bullets and guns didn't blow up !!!

I now quite a few who still use .411 in .408 - .410 bores.

The bullets are tapered so they are only .411 around the base and a little bit up the bullet.

If you are talking about 300 grain 405 Winchester bullets in a Modern rifle, there shouldn't be any problems. As stated above, I wouldn't use them in an older .408 caliber rifle like mine. I have a draw die and I take them down to .408 for me rifle.

The use of .411 bullet in a .410 bore is OK as long as it is not an a mono-metal bullet with a solid shank,like the older Barnes super solids with no driving bands,or the early X-bullets with a full diameter un-groved bearing surface. The solid full diameter Mono-metal .411 bullets are not, IMO, safe in double rifles.

.411 bullets that are lead core, or copper solids with driving bands like the North Fork, or GSCustom, are all OK in a .410 bore doubles.

Caution:The bore diameter absolutely must be determined before using any over sized bullet no matter the construction!

I will go along with every body else and say yes it is ok to use the .411 bullet in a .410 bore.
I have asked the enginers at Hornady and their answer was yes you can use it in the modern .410 double rifles with no problem.
In matter of fact, that what I entend to use for practice and all my big game hunting in the states.

Good shooting and God's blessings.

Malek

Thanks for the replies. I'm looking at using something like the 300gr Hornady Interlock soft point for practice and plinking. In a modern .410 DR.

Those 300 grainers are so soft they would work in any bore you could chamber them in. I use them all the time in my Krieghoff, Ruger, and custom Mauser .404 with a .410 groove Douglas on it. One thousandths difference is nothing in lead cored jacketed or all lead bullets. The problem comes in with old double rifles with thin soft steel barrels and steel jacketed or mololithic bullets.

dpcd

How come you have a 404 with .410 barrel instead of .423 ?

To give you more options in bullets ?