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rsterne
I found some time today to cast some of the new .22 cal Bob’s Boattails from NOE…. I used 1% tin in pure lead, and a temperature of about 840*F because of the tiny size of these bullets…. I have found the smaller the bullet, the hotter the temperature the lead needs to be, to properly fill out the mould…. They looked pretty good while I was casting them, no wrinkles on the body, but when it came time to sort them I found that over 2/3rds of the HollowPoints had a couple of small wrinkles so that the nose was not perfect…. Since some were fine, this is not a mould problem, but not quite enough temperature in the melt…. probably another 10*F would have made most of them perfect…. Alternately, a bit more tin might make the difference, but at over 800*F, the tin tends to burn out of the alloy, so just more heat might be the best answer…. Here are what they look like….
If you look at the HP on the upper right, you can see a couple of small divots in the HP rim…. compared to the perfect HP on the upper left…. In two hours of actual casting time (not including setup, melting the lead, and preheating the mould) I cast about 600 bullets, half were solids and the other half HPs…. Here is a photo of them….
The 2nd quality HPs are on the left (over 200), the solids are in the middle (nearly 300), and the perfect HPs are on the right (about 90)…. The solids weighed 29.6 gr. in this alloy, and the HPs were 27.4 gr…. and you couldn’t weigh any diference between the perfect ones and the seconds…. so I can use the seconds for Chrono testing and possibly target work, depending on how accurate they are, and I will save the first quality HPs for hunting…. As cast, the bullets were very close to the design size, which was 0.217″ at the back of the nose, 0.211″ in the middle, and 0.219″ at the rear band…. They were pretty good for being round, within about 0.0005″, and the diameters varied about 0.0005″ from bullet to bullet, just due to temperature and technique I am sure…. That’s what sizing dies are for, right?…. Here are photos of the beautiful NOE Moulds….
There is a Lyman style HP pin in one cavity, and this mould is for the smaller size that is available…. The larger one is 0.220″/0.222″…. ie 0.003″ larger in diameter…. Post continued below….
rsterne
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The barrel for my Regulated Disco Double project gun is a TJ’s designed by Sean Pero and I, and supplied by Mike for airgun use…. The designed dimensions are 0.217″ groove, 0.213″ land, with a 16″ twist, and I have to say, it’s very close to those dimensions…. I pushed through an oversized (.257) bullet and got a groove diameter of 0.2168″…. I purchased an NOE Sizing Die Body and some of their new airgun size bushings, so this was a good chance to try them out…. As part of the initial testing I will be seeing if there is any difference in velocity between differently sized rounds, so I ran some solids and (2nd quality) HPs through my new NOE Sizing Die, using bushings of 0.218″, 0.217″ and 0.216″…. This is the first time I have used the NOE sizing bushings, so I was curious as to how close they were to the size stamped on them…. It turns out that when I sized my bullets, at least with this alloy, they came out exactly 0.0002″ smaller than the marked size…. Here are the sized bullets, both Solids and HPs, and the bushings…. It is a great feature to be able to try different sizes at a cost of less than $10 per bushing…. As expected, the 0.218″ bushing didn’t touch the nose and gently sized the driving band…. the 0.217″ bushing just touched the nose in some areas on some bullets and sized the band…. and the 0.216″ bullet sized about a 1mm long ring at the back of the nose, and sized the entire band but without dragging any lead aft onto the boattail…. I wouldn’t want to size more than 0.003″ in one step, there was a fair resistance with the smallest bushing….
I took a few of the unsized solids and pushed them through some different .22 cal barrels I have here…. Now remember, the back of the nose is 0.217″ and the driving band is 0.219″…. The Disco barrel I had here required no effort at all to push the bullet through…. In fact, it FELL through the bore, from end to end, under it’s own weight…. So now I know that standard Crosman barrels can be pretty big!…. I pushed one into the barrel I will be using on my Regulated Disco Double (which at present is unchambered and unchoked) about an inch, and then back out the same end…. I had an MRod .22 cal barrel here, so I pushed three bullets into/through that…. one just past the port, one about 1/2 of the way through (both of those back out through the breech), and the other one right through from breech to muzzle…. There was a noticeable increase in resistance about 3″ from the muzzle, so it appears that the .22 cal MRod barrel is choked…. Here are the bullets….
The MRod bullets are on top, from L to R, through the choke, 1/2 way through the barrel, and just past the port…. My TJ’s barrel is the one on the bottom…. In the TJ’s barrel, as expected, the 0.213″ rifling engraved both the nose and driving band, pretty much missed the middle (as intended, to reduce drag), and the 0.217″ grooves shaved off a bit of the drive band, which was 0.219″…. In the MRod, the bullet (on the right) slid into the chamber right up to having the drive band just past the barrel port and then stopped and required a bit of force to chamber it past the port…. not a lot, you should be able to chamber it with the bolt…. In both that bullet, and the next one, which was pushed about halfway through the barrel, you can see rifling marks on the drive band, but none on the nose…. There are no marks from the grooves of the barrel on the one just chambered, but there are a few on the middle bullet, which indicates that the groove diameter of my MRod barrel is about 0.219″…. On the bullet that was pushed through the choke, you can see a few marks from the rifling on the back of the nose, and the driving band is deeply engraved, and in fact it is sized down by the choke, and now measures 0.218″…. This means that the riflng in the MRod barrel is only about 0.001″ deep, with the barrel being 0.216″ land and 0.218″ groove at the muzzle, about 0.001″ larger than that throughout the bore, and about 0.218″ land and 0.220″ groove just in front of the port…. I would think that these bullets, as cast, might work pretty good in a MRod, chambering without too much effort, sealing OK in the bore, and not losing too much going through the choke…. However, that is for someone with an MRod to test….
Bob
denisbeaudry
Got the mold in .220 “/.222″ cast about three hundred and did some preliminary testing . As cast they came out of mold at .2204” . Tested them in three different barrels . First was a Hatsan mod135 Springer, no go as there were rifling marks across the driving band. Next up was a LW barrel , no go again , same riffling marks on the driving band although not as deep. Next up was the Crosman 2260 barrel , near perfect fit ,no marks on the driving band will need to size them down . Looks like I’ll be getting the mold in .217 “to fir the LW barrel and the Hatsan and a few sizing dies . So guys and gals with a disco these will probably be the best option of the two . IMO
Rifling marks across the rear driving band would be a good thing…. I assume you mean the ones that were too tight had marks across the center portion of the bullet between the back of the nose and the rear driving band?…. That portion should clear the bore…. Rifling marks on the back edge of the nose would be good as well, but they don’t need to be full depth….
It is quite possible that barrels intended for pellets may need some work done on the chamber and/or leade to make it easier to load the bullets…. There is no reason such a chamber will not work well for pellets also….
Bob
Reworked , the chamber for bullets and it seems to have worked .
( Thanks Bob) I used the 400 grit sand paper technique ,and I use the term technique loosesly . The process didn’t take too long ,using 400 then 800 then 1500 grits to smoothen the transition out. I sized them to .2195″and they seem to chamber nicely with little force. I pushed a few out after being chambered and he riffling marks are consistent , riffling on the nose , none in the centre portion and slight markings on the rear band . Just for a secondary check I pushed a few JSB pellets with 5.52 mm on the tin , they had slight marks on the nose and none on the tail . Looks like I’ll need to go shooting and see how they work . kirbyolsen
I have the .250/.252 40g .250 and both the 30g .217/.219 and the .220/.222 but as soon as I received them it got very cold out and I cast outside so no rounds made yet…
Heck on the .22 I have barrels that need machined for the .25 Mrod breech so it will be a while for anything but push thrus to see what they look like…
Got an exhaust fan for the dungeon/basement window so should be going on the 40g .250 soon…
looking forward to hearing your results..
Here is some penetration and expansion testing of different pellets and my new Bob’s Boattails, both the 29.6 gr. FN and the 27.4 gr. HP…. All were shot in the mid 900s velocity range…. The test medium is my standard “Melt-and-Pour” soap, cast into blocks big enough to stop the bullet…. Here is a photo of the block with the four rounds inside it….
The BBT Hollowpoint is entering from the left (at 57 FPE)…. From the right, top to bottom, are the 18 gr. JSB Heavy (at 36 FPE), the 34 gr. JSB Beast (at 67 FPE) and the 30 gr. BBT FN Solid (at 57 FPE)…. Those FPE levels are the result of wanting all the bullets to be in the mid 900s fps range when they hit the block of soap…. The 34 gr. Beast had by far the greatest penetration, at 6.5″…. The 30 gr. BBT and the 18 gr. Heavy were nearly identical, at 4.2″ and 4.1″ respectively…. while the 27 gr. BBT HP exploded violently and dumped its energy by creating a large cavity before stopping only 2.4″ into the soap…. The volume of the wound channel in the block is roughly proportional to the FPE…. I then cut the block apart to photograph the wound cavities with the bullets still in place…. Here is the photo of the 18 gr. JSB and the 30 gr. BBT FN….
Now you can see why the BBT stopped in about the same distance as the 18 gr. JSB…. even though it had way more FPE…. The pellet hardly changed at all, which the large Meplat of the BBT expanded to well over bore-size, while leaving a much larger diameter wound channel than the pellet…. kind of the difference between an ice-pick and a sledge-hammer…. Next is the photo of the 34 gr. Beast and the BBT HP….
The block cracked behind the JSB Beast, so I didn’t get to photograph it, but the wound channel was long and thin…. and you can see the pellet was hardly changed at all by the 67 FPE impact…. Not so the 27 gr. BBT Hollowpoint…. It literally blew apart after entering only about 3/4″ into the soap, leaving three large fragments of the nose (and 1 small one) behind as the base (and 1 more fragment) continued penetrating…. More below….
Below is a photo of the bullets and pellets after recovery…. BBTs on the left, pellets on the right….
As you can see, round nosed JSB Pellets punch through and penetrate with very little change in shape…. Both pellets showed a very slight flattening in the center of the nose, and you can see how the skirts have obturated (blown out) from the pressure inside the skirt…. The Meplat on the BBT FN solid nearly doubled in diameter, showing how effective the large (70%) Meplat is in providing energy transfer to the target while limiting penetration…. The Hollowpoint BBT, however, is in another class entirely…. The nose section blew apart, creating a wound cavity in the soap nearly 3 calibers wide, while the rear portion of the bullet mushroomed completely and continued to penetrate, although less than 60% of the distance penetrated by the solid…. I would suspect that bullet to be devastating on Varmints…. and look forward to trying it out in the Spring….
Bob
denisbeaudry
kirbyolsen
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