Vintage spread shot pellets

Vintage spread shot pellets 

With thanks to John Griffiths, author of the Encyclopedia of Spring Air pistols, who conducted the following experiments. His findings include that using wadded shot charges in a rifled barrel imparts a spin, suggesting that the consequent centrifugal force creates a 'donut' pattern whereby the pellets are pushed towards the perimeter of the spread. Whereas a similar charge fired through a smoothbore barrel gives a more even spread pattern.

Writing on the airgunbbs.com, John said:

In a previous thread ( https://www.airgunbbs.com/showthread...d-shot-pellets ) there was a discussion about vintage spread-shot airgun ammo’, and since then I have received much useful information from John Atkins and I have also been experimenting with my homemade spread-shot pellets. Interestingly John tells me that he also experimented with making reproduction chalk shot pellets several years ago, in collaboration with the late Arthur Pickford, but unfortunately the test results seems to have got lost in the mists of time.

John says that the Star spread-shot pellets that I originally asked the question about in the previous thread, labelled ‘MODARCOM LONDON’were most probably made by Lanes Limited or Slugs Ltd (which was also part of the Lane group of companies) specifically for the Modern Arms Company (MODARCOM, later to become MARCO).

John is confident that the Modarcom spread-shot pellets were actually made at Widmore, Bromley. His reasoning behind this is based firstly on the fact that the Modern Arms Company Ltd., which was founded in 1923 at 133 Fenchurch Street. London, later opened another facility in Widmore, Bromley in Kent. Secondly, it is known that the later ‘Star' brand lead ball shot that came later onto the market (pictured below) were actually Lanes of Widmore Eagle slug boxes with wrap-around ‘Star’ brand labels stuck on them, obviously resurrecting the name from the old Modarcom Spread Shot boxes. Thirdly, Lane’s Ltd. of Bermondsey's registered a 'Star of David’ Trademark on 19th September, 1932 from their 45a New Church Street, London S.E.address. The Bromley area of WIDMORE connects both the Modern Arms Company and Lanes Slugs Ltd.

The original Lanes embedded chalk spread-shot pellets were sold in cardboard boxes, and then in square green tins. John informs me that tins of the pellets he has seen contained only chalk dust and lead shot when opened, and no complete pellets survived. It seems that they do not store well, and so we are not likely to find any surviving examples, and we have to rely on speculation and experimentation to get some idea of how these performed in practice. This is one the extremely rare surviving tins (photo courtesy of John Atkins).

For my homemade pellets, I found by trial and error that a good formulation for the carrier was a mixture of fine chalk powder (70%) and Plaster of Paris (30%) by weight. I mixed this dry and added it in portions with 12 lead shot into a mould (a hole drilled through a 3/8” thick brass plate), and tamped it down firmly with a metal rod. The top and bottom of the mould was then moistened with a drop of water, and after 5 minutes the damp pellet was pushed out of the mould and dried over a few hours in a warm place. Once dry, these could be handled without breaking and, equally important, they were a very snug fit in a .177 barrel.

The only problem was that making them was a very slow process. Making a decent quantity of the pellets would need some sort of a multi-cavity mould.

The weight of each lead shot and the number in each pellet needed to be decided. In the end I used No 9 lead shot (diameter 1.8mm, weight 0.05gm). The chalk pellets could be loaded with 12 of these, and the net weight, including chalk binder, was then very similar to that of a typical waisted .177 lead pellet. ( Joe Gilbart in his Guns Review article mentions that the vintage chalk pellets could contain 6 or 12 shot. I felt that 12 would be a better number for producing a decent spread.)

I tested the pellets in two of my rifles (yes, I do have air rifles!), namely an FLZ Original III (Millita), and a 1906 BSA. The BSA had slightly more power than the Millita (3.9 ft lb and 3.2 ft lb respectively), and also had a longer barrel, so the effect of these parameters on the performance of the shot pellets could be examined. The BSA is a tap-loader, but the pellets were short enough to fit into the loading port without compromising the tap. Both guns were rifled, which was not ideal, but was the best I could do.

Shooting the spread-shot pellets was great fun. When fired from either rifle, the pellets disintegrated completely and produced a cloud of fine dust, with what seemed an unusually loud report. No residual fragments of the chalk binder could be detected.

The most surprising observation was that the Millita, despite its lower power and shorter barrel, gave a significantly tighter spread than the BSA. I can’t easily explain this, unless it has something to do with the tap loading system of the BSA, or differences in the rifling. The following shows the difference in spread at a distance of 8 feet from the muzzle.

The spread of the shot with increasing distance, using the Millita rifle, can be seen from the following.

It is obvious that these spread-shot pellets are only going to be effective at very short range, probably no more than 20-30 feet depending on the power of the rifle.

The next question I wanted to answer was if the chalk carrier had any special advantages over simply firing the lead shot through the barrel with a tight-fitting wad. The following comparison, made at 16 feet with the Millita, is typical. The “wadded” test firing involved inserting a tight wad of oiled tissue paper into the breech, pouring twelve of the lead shot down the barrel, then pushing down a loose fitting plug of paper to hold the shot in place.

As can be seen, the spread of the shot is more or less identical in both cases. However, there was a tendency for the shot in the wadded case to congregate more around the edge of the spread circle, with very few shot at the centre . This would mean that you are less likely to hit what you are actually aiming at than if you used a single airgun pellet! Another obvious advantage of the chalk pellets is convenience – you can fire off half a dozen of these in the time it takes you to charge the barrel with shot and wadding. And you get the experience of the noise and dust cloud.

As far as penetration goes, each small lead shot does not have much momentum, but even so they could penetrate one side of an aluminium coke tin, or two sheets of 5mm corrugated cardboard at 16 feet.

Apart from the moral objections, this would make the spread-shot pellets inhumane to use on small birds, which had been suggested in the early adverts, but it could make them usable in a trap-shooting game of some sort.

A former member of this forum, well known to us old-timers as Norman, kindly sent me samples of modern shot cartridges and shot, among which were some tubular 0.22 shot cartridges of uncertain origin that were ideal for comparison with my chalk pellets. These consisted of a short green plastic tube, closed at the base with eight small perforations to allow air flow through them. The tubes contained 20 small lead shot of the same size as mine, and were sealed at the top with a card plug. Thanks to Elanmac in the previous thread we now know a bit more about these shot cartridges, and they were sold for a short while online, presumably as a small private venture that never took off.

Presumably the plastic casing was supposed to be retained in the breech after firing, and one or two of the cartridges did have a small burr around their base which would have helped keep them in place, but the majority lacked this and I found that when fired, the casing moved up the barrel and had to be removed between each shot. Very tedious when using a tap-loader. Occasionally the whole ensemble, casing and shot, left the barrel and hit the target as one, making a large hole in the target. Because of the increased weight of lead shot in these cartridges, I tested them in the highest powered air rifle I had, namely a .22 Webley Mark III, which was producing about 7.5 ft lbs. Being a tap loader, the cartridges had to be muzzle loaded using a long ram rod. The following shows the typical spread pattern produced from these cartridges. A comparison is made with simply charging the rifle with the same number of lead shot and a wad.

The wadded shot actually gave a smaller spread circle than the plastic cartridge, but the cartridge gave a more even distribution of the shot over the spread circle. Just as found with the .177 BSA and Millita trials, the wadded firing gave a pattern with the shot concentrated around the perimeter of the spread circle.

So we can conclude that confining the spread shot in either a chalk matrix or in a casing helps to give a more uniform distribution of the shot compared to muzzle loading with wads. This is an effect that John Atkins and Arthur Pickford also noted and discussed several years ago.

Later, he added:

Well I did eventually get round to using my smoothbore .25 heavy Gem to test the theory out. The doughnut type of spread pattern is only a problem with the wadded shot technique, as when the shot is contained in a ‘cartridge’ casing or embedded in chalk, you do not seem to see it.

So I used the wadding method with my Gem and packed about 16-17 of the small shot into the barrel, sandwiched between a loose fitting wad of tissue at the front and a tight fitting wad at the rear. I then recorded the spread pattern at a distance of 16 feet from the target. Here is a typical result, alongside a typical result, also at a range of 16 feet, obtained with my rifled .22 Webley Mk.3, charged with shot in exactly the same way.

So it is clear that rifling definitely causes a doughnut type of spread pattern, whereas with a smoothbore the shot spread is more uniform and concentrated over the point of aim. Interestingly the maximum spread of both patterns is about the same.

As a follow-on from the previous thread, John Atkins kindly sent me some vintage Spanish spread-shot airgun cartridges to check out. These dated to the 1970’s and were originally in the Joe Gilbart airgun pellet collection. Not much is known about them, other than that they are .177 calibre, were purchased in 1970 in Spain, and were called “Cartuchos M.G. Neumaticos” (M.G. air cartridges).

The cartridges consist of a short clear plastic tube containing about 8-10 small lead shot, with a 1mm air inlet hole at the base and completely sealed at the other end with what appears to be wax or shellac.

As they have no flange at the base the cartridge was obviously intended to leave the barrel when fired, and presumably the idea was that compressed air entering the hole in the base would propel the shot out of the cartridge, leaving the slower moving casing behind. This would also require the shot to have enough energy to pierce the seal.

When I looked at these, I must admit I was a bit sceptical. Firstly the air inlet hole seemed very small to do the job, and secondly the seal seemed to be too strong to be easily broken. I decided to put these to the test using my .177 Millita air rifle. This had reasonable power, and I also thought that the fact that it was rifled might help, as the rifling could slow down the movement of the plastic casing and help the shot accelerate ahead.

My misgivings proved correct, as every cartridge I tried failed to separate the lead shot from the casing, and the complete cartridge hit the target and made a single large entry hole. When the fired cartridges were located and inspected, they either still contained all their shot and had an unbroken seal, or more usually showed the seal broken but still retaining some of the shot. I reckon that the shot only left the casing at the moment the cartridge struck the target, and it was the momentum of the lead shot that helped to pierce the seal. These are typical targets:

So as they stand, the shot cartridges are pretty useless!

I next thought I would try modifying them, to see if I could get them to work as they were intended to, and the first thing I looked at was the effect of the size of the air inlet hole, which had always seemed too small to me. The hole was enlarged from 1mm to 2 mm (any larger would have let the shot fall out). However, this had very little effect, and after a number of attempts only one test shot showed signs of the shot leaving the casing before impact when just three pellets penetrated the target, with the main casing making its own large penetration hole. All the other attempts showed only the single intact cartridge hole on the target.

The other variable to consider was the strength of the seal, as if this is too strong the shot would be unable to pierce it. It did seem very tough to me, and it took some scraping to remove it. I prepared a few shot cartridges with the air transport hole enlarged to 2mm, and with the seal removed. A very loose plug of tissue was inserted in place of the seal to stop the lead shot falling out. However even these doubly ‘improved’ cartridges failed to work, and none of those tested showed any sign of the shot separating from the casing before the cartridge hit the target.

So how these cartridges were ever expected to work I do not know. Perhaps they worked with high power FAC rated air guns?

In conclusion, of all the methods for producing a spread shot effect from a moderately powerful air rifle that I have tested, the chalk-imbedded cartridge is the most reliable and convenient.

The original spread-shot pellets patent:

John further added:

I wondered if the fact that these were 50 years old might have been a factor in their abysmal performance.

The hardening of the seals over time no doubt has happened, as the seals are brown and very tough and brittle. However, the fact that the cartridges still did not work when the seal was removed discounts this as a contributing factor.

The lack of tightness of the cartridge in the barrel might be the main culprit, if the plastic had shrunk over time. Although the cartridges were a good tight fit in the barrel of my gun, I had a look at making them even tighter. I expanded the base of a couple with heat (they seem to be made of polythene or polypropylene so could be shaped with a bit of heat) but this still did not result in the lead shot leaving the cartridge case. Finally I deliberately splayed out the base of a couple of them, as here:

I enlarged the air entry hole to 2mm, and then broke up the seal so that the shot faced very little resistance to leaving the casing. The results with these were much better. The casing did leave the barrel but did not reach the target (range 16 ft), whereas all the lead shot hit the target with reasonable force. However the spread was very wide.

So it seems that these cartridges can be made to work if they are sufficiently tight in the barrel. However, it is difficult to see how this tightness could have been achieved with them in their original form.