Some of William Metford's letters to Sir Henry Halford survive and give a fascinating insight into the experimentation conducted by these gentlemen in the pursuit of accuracy. This short collection of extracts from their correspondence covers work with bullet alloys.
The information in the grey background is extracted from letters written by William Metford to Sir Henry Halford. It was published in the Journal of the Historical Breech Loading Smallarms Association.
13 April 1870
"Tried a weak alloy of lead and tin to see difference in drop. Present alloy, 20oz. of antimony to 1 cwt. of lead and 4 lbs. tin: against the weak alloy, 4 lbs of tin to 1 cwt. lead. 600 yards, 3ft. (full) difference."
Under imperial unites 1 hundredweight (1 cwt.) is 112 pounds.
The "weak alloy" therefore appears to consist of 112 lbs of lead and 4 lbs of tin. This may be thought of as either a 3.57% alloy (4/112) or a 3.45% alloy (4/116), depending on the convention you prefer for representing alloy proportions.
The "present alloy" appears to consist of 20 oz (or 1.25 lbs) of antimony added to 116 lbs of the weak alloy, giving a lead/tin/antimony ratio of 95.5/3.4/1.1.
19 March 1871
"Re bullets. Blue [THE PAPER PATCH] are the latest, and consist of 25 lead + 1 tin + 4 antimony, commonly called 8 + 1 pig because a pig of 25 lead and 1 tin = 56 lbs, and to this 56 lbs 8 of antimony are put. The paper should be thus [ROUGH SKETCH INCLUDED]. The depth of hollow should be 15 to 16 hundredths. I fancy the white paper bullets will have a greater depth of hollow, aye? Probably they are 10 + 1 pig, i.e. 25 + 1 + 5. If they are deeper in hollow they should be restruck up. The slight difference in hardness is I think of no moment."
Metford text above includes : "25 lead + 1 tin + 4 antimony, commonly called 8 + 1 pig because a pig of 25 lead and 1 tin = 56 lbs, and to this 56 lbs 8 of antimony are put."
This can be considered as follows:
One pig means one 56 lb block of lead/tin alloyed in a ratio of 25 lbs of lead to 1 lb of tin.
8 + 1 pig means 8 lbs of antimony plus one 56 lb pig of lead/tin alloy, for a lead/tin/antimony ratio of 25/1/3.7
10 + 1 pig means 10 lbs of antimony plus one 56 lb pig of lead/tin alloy, for a lead/tin/antimony ratio of 25/1/4.6
Keep the above explanation in mind when reading the following correspondence extracts:
25 April 1879
"I tried 8 + 1, 4 months, versus 14 + 1 older. 2′ at 1000 in favour of 14 + 1. I shall make up 6 + 1 anyhow, say 5000 to start with."
If I read the above correctly it appears that with the 14 + 1 alloy he could use lower elevations. Looks like there was some serious experimenting planned – 5000 to start with!
19 November 1879
"Just a line. Hard at work cutting barrels for Deeley, and bullet alloy experiment."
no date but 1879
"Just a line to say I am sending off a lot of 8 + 1 old, different papers, as against 4 + 1 Pig."
"If 8 + 1 Pig would do for slow powder – it has done for C and H 5. I used it for years and only altered for breechloaders. 4 + 1 Pig I find from experiments (Pendulum) is only 10ft. per second behind 8 + 1, if as much."
So it appears that for Metford’s muzzle-loading rifles he used 8 + 1 Pig alloy.
18 August 1880
"I ordered off (sent too) a box of 250 590 grs. 14 + 1 new and about 300 540grs. 8 + 1 ripe, on relation to sawdust, especially in re slow powder."
"The rifling of the 560 lot sent is peculiarly charming but I recollect that one bullet you got out of the sawdust with no rifling at [sketch of bullet section and arrow pointing at portion of bullet immediately above base] !!! It is too close a shave, but observe it was really done to use up 14 + 1, a metal really arranged for C and H 6. The 560 grs. bullets and which we both used up to now have been getting harder and harder, and now are a bit too ticklish."
"I reckon that the 590 grs. new 14 + 1 (= to 8 + 1 ripe) will rifle just right (can you try it?) with slow powder."
Metford appears from the above to have been experimenting with different alloys for different powders. I was also interested in the comments on the difference between new and ripe bullets.
28 May 1871
"I sent off Friday some bullets, 200, of 3/4 anty., 2 tin, 50 lead, old and fully ripe and restruck up to .460 diar. instead of the usual match size of 452.5-453.5. Also 200 3/4 anty., 2 tin and 50 lead, new .460; the last are at present too soft, I suppose. They are clearly shorter and being also larger will be liable to distortion."
The above gives further comment on alloys and softness/ripening.
A fascinating topic and probably few of us have the time or resources for such experimentation today.