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Post by edge on Jun 28, 2011 20:44:28 GMT -5
Well on Sunday I got a PM from 500cadillac asking if I had tried Delrin as a sabot material. It had been one of my first plastics when I started with the inner sabots in 50 caliber. I told him that I had not tried it with a rifled sabot but I did not remember why. When I started with the 50 caliber I made 2 piece inner sabots, some with bottoms but most without and relied on a washer or an aluminum disk made by Falcon, a former member. Most plastics had problems and I don't recall why Delrin was not at the top of my list, but is was not At any rate I had about 2 feet leftover and decided to try it rifled. I tested a few tools and came up with a reasonable procedure for the Delrin and a few more sabots the diameters seemed where they should be. I made the sabot to the same dimensions as the PVC-II sabots that are my Gold Standard and I made them for the .338 180 grain Accubond, which is a very stable bullet. I got out a few minutes early and there was no traffic so I was able to head to the range for a few shots. As luck would have it there were two other shooters there and were in no hurry. One got a phone call so I set up my target and rushed to get ready and forgot the greased wad. The bullet was incredibly hard to load but I got it down. The shot was not where it should have been and that was when I realized that the wad was not loaded......I had two targets side by side and I had aimed at the left target center and it hit on the right target about 2 inches high. What to do? I decided to shoot another shot and aim at a spot that should hit near the first shot had it been shot correctly. At this point it was just a guess! The second shot almost bent my range rod getting it down to the powder. At the shot I saw that it hit almost exactly where I had anticipated so I loaded another and loaded with a mallet to drive the third bullet down. I was very happy to see it hit within 1/2 inch of the second shot even though there was no definite sighting spot. Well, I have about a foot of material left and will try one or two designs to see if they will load easier. I had anticipated that it would behaved like a slick PVC but it does not. I'll reduce the pressure points with the remaining material and with a bit of luck have a few to test on Friday, since I have the day off. At any rate, here are the three shots. edge.
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Post by 500cadillac on Jun 29, 2011 1:01:19 GMT -5
Delrin is non-corrosive right?
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Post by dave d. on Jun 29, 2011 7:30:22 GMT -5
looks like a good start. Goodluck Friday bud
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Post by edge on Jun 29, 2011 7:55:59 GMT -5
White Delrin is pharmaceutical friendly so I do not anticipate any corrosion issues, but I'll find out on Friday as I did not clean my barrel after shooting those three shots edge.
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Post by Deleted on Jun 29, 2011 9:26:55 GMT -5
Is that delrin100 ? I noticed there are a # of delrin products. That might be the sabot solution. Thanks Edge for trying it out. Greenhorn
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Post by Richard on Jun 29, 2011 16:22:55 GMT -5
Greenhorn...............the only problem is........they are not available to the public Not unless you have a close friend with access to CNC machinery? Believe me, Edge's PVC sabots shoot great.......I know, he supplied me with 10 and I have shot five . I'm "hoarding" the second five ;D All he does is get everyone excited. Maybe in ten years or so when he retires, he will buy some CNC equipment and sell them to the board ;D Richard
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Post by gunny on Jun 29, 2011 16:34:32 GMT -5
When can i place my order ;D
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Post by littlejoe on Jun 29, 2011 17:28:11 GMT -5
Edge, Delrin is a great material. Dense and strong, able to be machined and hit consistent sizes. In the shipyard the toughest plastic we used is called "Thordon" It is used to make bushings and bearings in high wear areas. I have even seen it used to sleeve worn bronze Cuttlass bearings as a bandaid untill the next overhall. It is expensive, but has some unique qualities. Joe
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Post by jims on Jun 29, 2011 17:44:09 GMT -5
My sister just sold her deceased husband's machine shop, including tooling, tools, various machines and a CNC at a reasonable price. Unfortunately much was three phase and I just would not use it enough to warrant having it. It would be nice to have regular access to the same, so many possibilites. I can't wait to hear edge's Friday report. I had thought about Delrin but I figured it was tried and did not pass muster for some reason. Apparently it offers some possiblities. I have used it in some outside projects and it has worked well for my applications.
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Post by Deleted on Jun 29, 2011 22:15:35 GMT -5
Richard, If Edge can make something that can work out of delrin , then there is hope. To say available is another question. There has to be a material already man-made that could be useful in the sabot application"smokeless" that is. Maybe Thordon which LittleJoe refered to might be another alternative. I'm looking at selling my guns so I can get a little lathe and see for myself what can be done about the curse. Good luck Edge, Greenhorn
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Post by olegburn on Jun 30, 2011 13:48:24 GMT -5
Edge,I think that lot of us reading your posts with your work (custom sabots) are feeling like we watching Sci-Fi or reading Popular Mechanics magazine. It is soooooo unavailable and futuristic to us. We want future,now! ;D
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Post by Richard on Jun 30, 2011 14:58:07 GMT -5
Greenhorn........go for it! We need more "tinkerers" Richard
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Post by rangeball on Jun 30, 2011 15:01:07 GMT -5
I just had a thought. Edge's machined sabot is a proven design that works with high BC bullets. If he could mass produce them for sale or have them produced for sale, I wonder what the cost would be plus an existing bullet compared to the new CEB bullet we are trying to develop?
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Post by 500cadillac on Jun 30, 2011 16:54:12 GMT -5
I just had a thought. Edge's machined sabot is a proven design that works with high BC bullets. If he could mass produce them for sale or have them produced for sale, I wonder what the cost would be plus an existing bullet compared to the new CEB bullet we are trying to develop? If you are going to use machined sabots then you need a fast twist barrel, like a 1:14 or faster to make proper use of small caliber bullets.
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Post by edge on Jun 30, 2011 17:32:22 GMT -5
If you are going to use machined sabots then you need a fast twist barrel, like a 1:14 or faster to make proper use of small caliber bullets. Not 100% true, my custom 50 had a 1:20 twist and the 150 grain 8mm Sierra is/was my bets bullet ! My stock 10ML shot the 180 grain Hornady SSP very accurately too! True, I see no reason that a 10 twist can't shoot a .338 300 grain SMK to 2k... but how many want to or have the need. If I ever build a ML on a custom barrel again it will have a 9.5 twist just because it can Can a rigid sabot be molded accurately enough to be usable I don;'t know! I bought a small extruder years ago and using a barrel drop have not been successful with it. Perhaps if I had a wire EDM I could experiment enough to make it work for my barrel, but could I make it universal? Now if I had the inclination, I would build an oversize mold and require the user to pick a polyethylene plastic shim to go inside to make the load user friendly. On the old board I asked what folks might be willing to spend to make a high BC bullet work and most were not in favor of an expensive sabot even if they could shoot a high BC bullet. Has this changed? IMO, I would only advance this if folks were actually putting up funds to make it work. Too often people jump on the bandwagon only to jump off when funds are asked for IMO, a rigid sabot without some "filler" will NEVER be a fits all even if the twist is uniform. edge.
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Post by rangeball on Jul 1, 2011 10:55:12 GMT -5
Are you talking R&D funds or actually buying the product if made available?
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Post by Deleted on Jul 1, 2011 11:23:54 GMT -5
Edge, Are you familiar with the Lightfield Hybred mag-20 slug with the two-piece sabot design ? Any thoughts on that concept in a sml ? I believe they are made for rifled barrels. Its kinda like full bore nose ,saboted body,and full bore base "lead" . I saw an article in BUCKMASTERS about it and other bullets and the author raved about how ultra-accurate they were. Nobody carries Lightfield slugs around here , I would like to see how the 2piece sabot works. I did not know if you had seen them or not... Greenhorn
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Post by Deleted on Jul 1, 2011 11:39:23 GMT -5
Just another thought,what if you had a bullet with a base that had small gear cuts. The sabot also would have a geared face that would mesh with the bullet essentially locking them together torque- wise , I would hope that the flaring petals would be enough for dis-engangement. Another member brought up knurling the base, i guess this is just a little upgrade to that thought. Would the design help anything who knows, just ideas.
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Post by Jon on Jul 1, 2011 12:18:24 GMT -5
Edge looking for further info. I'm sure it is a dumb question but would it be possible to make a blank grove size sabot and push it through a form fit die. I know way back you tried it with a barrel drop but with the adjustable die would you be able to match it to bore. That would take a step out of production I would think? I asked you about UHMW before but I don't remember the answer? I used to have more success with it in some application's. Obviously not for a sabot. This may be apples and oranges if so ignore. Jon
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Post by rossman40 on Jul 1, 2011 12:47:26 GMT -5
The Lightfield Hybred is just a follow up on the BRI slug design which came out in the 70s (still sold by Winchester), Lightfield Hybred BRI The advantage is if the bullet tries to go forward or to the rear in the sabot the "hour glass" shape not only keeps the projectile centered but actually swells the sabot. Now this works well in a low pressure situation (shotguns have a lower chamber pressure then even BP rifles) but in a high pressure situation this would be like applying the brakes and would be very dangerous. Chamber pressure would rise and and the more pressure applied to say the base of the bullet the harder the brakes would be applied. It would result in fouling at least but you could also see a pressure spike "like you ain't ever seen before". The design does give you a center of gravity well in the front which gives good stability, even when the projectile goes sub-sonic. But, you end up with the sucker flying like a badmitten birdie and it looses velocity fast. Lightfield went a step farther and attaches the wad to the base. A lot of the newer design slugs are going to the CG being as far forward as possible and leaving the wad on. The old Brenneke Rottweilers did the same years ago and their newer Brenneke KO does the same.
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Post by edge on Jul 1, 2011 14:45:45 GMT -5
A whole bunch of questions The Lightfield type sabot could not be loaded since is not pre-rifled...IMO. A sizing die has never worked for me since the plastic has too much memory. UHMW plastic is too soft for my process. A two piece rigid sabot can work but they are a pain to load and they were not as accurate as my 1 piece so I stopped trying. edge.
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Post by littlejoe on Jul 1, 2011 15:07:11 GMT -5
Edge , I posted earlier about Thordon and was wondering if you had heard of it ? Or considered it already and found it to be desirable or not ? I would be glad to send you a piece to try. Joe
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Post by mountainam on Jul 1, 2011 15:32:04 GMT -5
Rossman40, I used the original BRI sabots in 1971 when they first arrived on the market. Everyone thought we were nuts for paying $2 for a box of 5. The originals used real white Teflon for the sabot. Then Smith and Wesson bought them and then Winchester and Federal used the same or similar design but had a lubaloy coated slug. My point is that the Teflon sabots shot the best and when they switched to the other subsequent plastics they shot OK , but not near a accurately as the BRI originals. They probably changed materials due to costs of the Teflon. Now we seem to hear a lot of negative info concerning Teflon lubes etc as being detrimental to accuracy. I wonder if Teflon Rod is available to make sabots for our rifles?My Savage 210 still shoots that type of slug more accurately than any others.
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Post by mountainam on Jul 1, 2011 15:55:19 GMT -5
Edge, There is a company that makes .50x .30 cal sabots for the Military's .50BMGs. I can't remember positively the Company's name (perhaps R&R supply), but I know it's located in Ursem,UT or is it Ersem, UT? They are made of extremely rigid plastic that you may be able to work some of your magic on. They remind me of the old Remington's Accellerator sabots. This outfit also makes sabots in .30x.224". Maybe they are the ones that made sabots for Remington. I bought them to use in a ML but I couldn't beat them down the barrel. Now that I'm thinking about it they may work for the guys that bought the off-beat Knight.52's because they mic at .510".
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Post by edge on Jul 1, 2011 16:14:11 GMT -5
Edge , I posted earlier about Thordon and was wondering if you had heard of it ? Or considered it already and found it to be desirable or not ? I would be glad to send you a piece to try. Joe Thanks, do you know what the plastic family is and not the trade name? For instance, Delrin is a trade name for an acetal homopolymer. If I know the family then I would know if I have tried it or not, the price and local availability. edge.
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Post by edge on Jul 1, 2011 16:17:05 GMT -5
I have about 900 of those BMG sabots, they were too much effort to make usable in a ML. edge.
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Post by rangeball on Jul 1, 2011 16:20:16 GMT -5
I have about 900 of those BMG sabots, they were too much effort to make usable in a ML. edge. Can you expand on the particular troubles they presented?
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Post by edge on Jul 1, 2011 16:55:46 GMT -5
They had to be machined on a mandrel with a live center. The petals tended to crack and the inside molded shape is not ideal, it is a hex shape if I recall and the exterior is designed for a cartridge and does not have a funnel shape to enhance petal separation. The petals do not go all the way to the bottom so separation is probably not uniform.
I know of no one that reports sub 2 MOA accuracy in a BMG.
edge.
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Post by littlejoe on Jul 1, 2011 17:05:47 GMT -5
Edge, this is what I could find. Elastomer polymer grades SXL, HPSXL and XL. Down at the bottom of this page in the Thorflex section they can formulate material specific to your needs. I also noticed that they offer high strength polymer impregnated with lubricant. www.thordonbearings.com/pumps-industrial/other-industrial Joe
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Post by edge on Jul 1, 2011 17:10:36 GMT -5
Do you know the cost?
edge.
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