Just out of curiosity, does it appear the fore end was replaced at sometime in its life? I once owned a similar engraved Field’s patent rifle same cartridge in fine condition Sold it to a gun writer quite some time ago. Bought dies for it from the UK. If I recall spent more on dies than the rifle.

I think the 461 had a lighter bullet also - about 340 grains.
I'm not sure what the unpatched bullet diameter would be, but a papered bullet and black would be the easiest way to get it to shoot.
J H Walsh's epic 1883 tome "The Modern Sportsman's Gun and Rifle Vol II" may shed some light on the matter.
If you Google the title, I believe you can find a readable archived version on the UCLA website.

About what weigh/length bullet will be correct.  We can likely come up with something. We make 45 calibers up to .468" diameter.  We can custom blend any binary alloy you want and lube for black or smokeless powder.
The Bullshop

bullshop wrote on Jan 10^th, 2026 at 12:01am:


Anything 500 grain-ish for a starting point....round nose preferably.  I believe something like the Saeco 881 or similar, sized to .461 would be a great place to start.  Not a ton of info out there on the Gibbs #1...so don't have many specifics...just looking for a place to start. Will be black powder, so 20:1-ish alloy I believe would be in order.

We have a .468" at 500 grain-ish for the 577-450 MH.  We do not have a .463" sizer.  You can custom order any sizer diameter you want from Lee Precision in their loading press type push through sizer.  I have many of them but not what you need.  With your custom sizer in hand you can size our .468" to your desired diameter.

Your aversion to paper patching is holding you back from success.  The rifle was made to shoot paper patched bullets.  Do it!

Secondly, your bullet diameter is limited by your chamber neck dimension.  I think you will find that a bullet of sufficient diameter to fill your bore or throat will result in a cartridge that will not fit in your chamber.  If you make things too tight in the neck you are courting danger.  

I am loading for my original Gibbs-Metford Farquharson MBL target rifle. .461 No. 1.

To begin, I used plug gauges to determine my chamber neck diameter and worked dimensions back from there.  Specific to my rifle only, I found that a .485” plug goes freely in the chamber neck, whereas a .486” plug meets interference.  Neck thickness of my brass is 0.011”, so the brass takes up no less than .022” of the neck diameter.  Thus, the absolute largest diameter bullet I can load would be .463”, but that’s taking it to the limit.  You need some clearance.

My research told me that the Gibbs No. 1 round was loaded with a lead bullet of .451” to .452” diameter with a paper patch bringing it out to about .459”.  The soft lead bullet would conform to bore dimensions when launched by the sudden impact of black powder.

Bringing it full-circle, I am loading a swaged bullet from BACO - their excellent .451”, 480 grain paper patch bullet.  Using two wraps of 9# onion skin, my bullet finishes to .457” to .458”.  That gives 5 or 6 thousandths clearance in the neck, which you will need for bullet release and to work around fouling.  My latest load is this bullet over 75.5 grains of OE2F, a CCI 250, topped with a beeswax foundation wad, ¼” grease cookie, all with an OAL of 3.170”.  Your powder charge must be compressed to the exact depth to accommodate your wad column and bullet.  The bullet will not do this compression.  You must use a compression die, properly calibrated.

If you plan to shoot these antiques you must conform to loading practices in use when they were made.  Modern components and practices often are not appropriate.

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Good luck,
Curly