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I have a AR 15 Colt HBAR 5.56 with the 1-7 twist. It handles jacketed bullets very well in the accuracy department. Long ago I decided to try cast bullets in it. To tell the truth I didn’t have real good success at finding an accurate load. Not too long in the past a friend and I decided to design a heavy cast bullet specifically for the 5.56 chamber. I did the chamber cast and gave it to my friend and he drew up a bullet to fit it. Not long after I receive a beautiful four cavity mould and I am casting bullets to try in my AR. We ended up with a bullet that weighs very close to 65 grains when cast of 50/50 alloy which is pure lead and wheel weights mixed. To make a long story short, I wasn’t having very good success in finding an accurate load in the 2400 fps range. I tried different fillers. I tried buffer. I tried many powders, a few of which produced 1.5 MOA with normal loading procedures at around 2150 fps velocity. I even tried duplex loads, which lead to some success. It seemed I was stuck at a low 2150 fps velocity range. If I went above that, accuracy deteriorated fast. I thought many things. One thing I thought was there was no way that I could possibly cast 100 % of my bullets with voids or flaws. I had a quality rifle with a good trigger. I had my bench shooting down pretty well. Something else was causing the problem and it clearly wasn’t rpm. I though perhaps it could be the cast bullet material not being up to the task of handling fast twist rifling at higher velocity and pressure. I thought back on my duplex loads. I’ve gotten those to work very well in other calibers and rifles. Then I struck upon something. I started thinking about what Hornady and Hodgdon were doing with the Super Performance Powders. Right away I started on blending my own “super performance powder”. I studied what Hodgdon had done and the writings of a very good ballistician Bob Forker. Now home blending is going to be a very taboo thing to many here. With that in mind I’d like to say that you should study up on this thoroughly, talk to ballisticians, maybe even PM me to see what I have done. With that said I’m not going to say which powders I blended or the amounts, but I am going to tell you what happened when I shot them. I blended what I thought would work after proving a duplex load with the same amount of booster and main charge that worked and shot with coke can bottom size groups at 100 yds. From there, I cautiously worked up the load. Previously to this, I was stuck just right outside of about 185,000 rpm. My first attempt out on the target range produced a ½ inch five shot group. This group was repeated over and over. The rpm for that group was 210,651 rpm. Then I upped the load to get a rpm of 220,114 rpm. A ten shot group did a repeatable 1 inch group. Since then I have purchased some of the Hodgdon Super Performance Powder and tested it. Although it gave the exact same velocity as my blend, I did not by any means achieve decent accuracy with it. The factory blends powders to meet their requirements, and clearly my blended powder was vastly different then Hodgdon’s. Different requirements necessitate different blends. That brings me to this part of the story. There’s a fellow from another forum that preaches cast bullets have narrow range that they can be fired in and achieve accuracy…useable accuracy. He concluded that it was the rpm of the cast bullet that was limiting its accuracy range. He had a name for his unproven theory which he called The RPM Threshold. Now I say it’s unproven because, although he could show that within his rpm threshold a bullet could be accurate, but could not definitely give a reason why a bullet outside of that threshold was inaccurate. Oh he tried with such things as “voids in the cast bullet” or “other flaws” would be acted upon by the rpm of the bullet to cause it be very unbalanced thus inaccurate. He also came up with things like double helical spirals and many other jibber dash theories….none of which he could prove. So in closing what have I proven? I proved that the rpm threshold theory has some really big holes it can’t explain. It’s unproven only in the fact that the inventor cannot tell you why he could not achieve accuracy out of his rpm threshold. I’ve proven with no doubt that cast bullets can be shot at a higher velocity and rpm then our rpm expert suggested. What I have not proven is what exactly is happening. What did this powder that I blended change? Some will say that perhaps I got a softer launch for the bullet at its initial beginning in the chamber before fully entering the bore. I don’t know. I do know one thing for certain. I know that the rpm threshold theory isn’t right. I’ve narrowed it down to pressure and the strength of the alloy. I believe with my 7 twist rifle that I was at or a little past the limit of my 50/50 alloy, but why did my blended powder allow me to pass that limit? Can’t really say it was lower pressure because I had a much higher velocity with the blended powder so the pressure couldn’t have been lower than the loads I was previously stuck on. All I could think of is that the powder spread out it’s “push” on the bullet over more of the barrel…lots more. I don’t know that for sure. What I do want to know is if the strength of the alloy is exceeded why does a faster twist show problems first? Even if the entire bullet is in the plastic state from being push beyond its limit we know that the bore will contain it. When you recover such pushed beyond their limit bullets the rifling on them show very little if nothing at all as to what is happening. Could it be the nose has changed from all the pressure behind it trying to compress the bullet? We know you can’t really compress metal so the moved metal has to go somewhere and being confined in the bore it has to go towards the nose and perhaps change it somehow. Could whatever is happening to the bullet be exaggerated as it leaves the muzzle? Could the shape of the nose be changed from all the pressure and once it hits the atmosphere it can’t possibly fly true? What I do know is it’s not rpm causing the problem. Even pure lead that is paper patched can be driven to very high velocities and rpm. Now I’ll move on to other calibers and see what I shall find. There are some other shooters I have spoken to about this that are going to start their own shooting. | ||
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What? No one hole group all day long? What in the world do you think was the malfunction? You going to have to go back to blending school? I exceeded the rpm's on a 45 rpm record, played them at 78 rpm's and it sounded like "The Chipmunks"--maybe a varmint load? Gosh I wonder who this person from another forum could possibly be? | |||
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I tripped on my rpm threshold. Need to paint it orange so I can see it. Anybody know of a good paint to use? | |||
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I'll take a stab at it. I think the blended powder flattened the pressure curve and then dumped it right before muzzle exit. Your blend happened to give a gentle launch, a long, powerful burn, and quit just before the muzzle for a low-pressure, accurate exit. Did you notice anything funny about the report or flash with the blended powder vs. any of the other duplexed combinations or any other powders you tried? I would think something would stand out in the way these act when leaving the gun compared to all the other loads that didn't group. Part of the hicky with "rpm" is that increasing velocity with ANY powder or gun tends to increase muzzle pressure, one reason why Unique and 2400 work so well for reduced loads. Any tip or jetting at muzzle exit is exacerbated by the pressure increases. Slower twist rates seem to increase accurate velocity, but I agree that THAT is strictly related to boolit strength against the lands, and I think shear and torque forces on the boolit damage it as it emerges from the muzzle. Paper jackets prove it isn't casting defects or nose slump (as a rule) that causes accuracy to tend to fall off as velocity is increased, harder, tougher boolits and slow powder extend the useable velocity, but not much with normal loading techniques, so all that points to something happening right as the boolit comes out of the muzzle to ruin accuracy. We know that using compacting buffers in certain cartridge shapes can help protect the boolit base from muzzle jets and thus improve accuracy at HV, but it doesn't work with everything, and only works with certain powders in the cases most suited for it. So the bugaboo isn't necessarily boolit base. If it isn't base damage, and it isn't nose slump, and it isn't voids, then only a few things remain to explain the accuracy/velocity/twist thing: Getting the boolit started straight, making the boolit strong enough to resist excess deformation by the lands under acceleration torque in fast twists, and ensuring no damage at muzzle exit. A paper jacket protects the land engraves from damage and enables copper-jacketed velocity and accuracy with or without fillers, and also protects the boolit at muzzle exit, so those are key things to relate to how RPM affects accuracy with grease-groove boolits. The only thing really left to explain said "RPM Threshold Theory" is land engrave strength. I don't believe boolits can strip in the bore, but SOMETHING is happening to the engraves or at muzzle exit to damage the boolit. It's either the surface strength of the boolit, the torsional strength of the boolit as it suddenly breaks free of the torque load of the barrel, or muzzle pressure that's causing groups to open up when spun too fast. High muzzle pressure from powders that are too slow for good muzzle exit (but considered by many to be essential for gentle initial engraving without damage) to be a major culprit with the accuracy drop off, and fast twists do something funny to the boolit as it pops out of the muzzle at high velocity. Getting muzzle pressure down and still having good launch characteristics has to be helping, that's why I think you found the perfect powder burn rate for your particular gun. Gear | |||
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Thanks for the reply Gear. I can't say I really noticed a difference in muzzle blast, recoil, or muzzle flash with my blended powder. Believe me I was paying attention when I fired the test round because I've never blended powders before and wanted to be safe. I feel what you said about the alloy being strong enough to withstand the rifling engraving goes along with the material strength of the alloy. As I have said I believe I was right at the limit of my alloy's strength with my fast twist barrel. Soon as you get that report back from the doctor on what the pressure of the alloy is against the land sides we'll know more. | |||
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I'm going to bug him about it again, keep forgetting. Curiosity is eating at me. I really think you're on to something with that blended powder, but what exactly it's doing is hard to say. You don't happen to know anyone with a personal ballistics lab, do you? Gear | |||
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No I don't know anyone with a ballistic lab, but I sure wish I did. Heck I'd even settle for the 4895 Man to get pressure reading for me. | |||
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Yes interesting. I've been through all that years ago. One thing I don't have any problems what so ever with my chronograph picking up those .224 caliber bullets. I've used the boosters and as noted in the original post on this thread I'm blending now. I don't have any ignition/powder burn/standard deviation problems with using a RCBS type expander and NO crimp. So I'm not buying the taper crimp thing. Another thing that can be tried is a mag primer. My velocities with just 860 and no booster were around 1960 fps and with the booster about 2400 fps out of a 7 twist 20 inch barrel. We talked about this. | |||
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Oh, I know you got it nailed. I just thought it was interesting. Gear | |||
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Does 2415fps in an 8 twist barrel with a 160gn soft nosed-hard shanked 7mm cast hunting bullet count in the RPM stakes? | |||
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Sure does, what kind of accuracy you getting with it? In a 9 twist your rpm is 193200 and in a 9.5 twist it's 183031 What alloy is the shank made from? Bullet mold??? Thanks for replying | |||
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I get in the 1 1/4 - 1 1/2 at 100yds so it is good for about 250yds. I have taken game (goats) to 185yds so far. 60gn 50/50 (ww/Pb) nose on a lino shank and in a 8 twist x 25in barrel so running at 217350rpm with expansion to .577 and 100% weight retention. 39gn H4350 / WLR gets me the 2415fps and works for me. Thius might be of interest http://www.mausercentral.com/f...iewtopic.php?t=32271 | |||
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Von Gruff Very well done. You have something there that you have proven to be very effective. Thanks for sharing it with us. | |||
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Joe Glad to see you've come back from the dead....... I see you've come up with another recipe for shooting moa and less and HV with cast bullets.......this time it's a special blended powder that no one else has or can duplicate.........oops, it two special super secret things!!! A custom designed bullet (by you of course) and the special blended powder that only you figured out.........amazing! Larry Gibson | |||
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It certianly does. You've done most everything right to push the RPM threshold higher with your cartridge/rifle; custom bullet with hard shank and minimal lube grooves to minimie distortion during excelleration, a slow burning powder and a long barrel. That bullet design is similar to the 150 gr LBT bullet that is successfull at 2300 - 2400 fps in 10" twist .30 cals and the 311466 I use with the nose swaged. The OP here always seems to forget the RPM threshold is not a limit. It can be moved up or down with the use of the correct loads. You and I have discussed this at length and what you've done is very good indeed. However, someone with Yugo M48A or a M95 Mauser with the typical bore rider cast bullet available these days cast of WWs is not going to get any accuracy above 1900 fps......because that's where the RPm threshold for that will be. Larry Gibson | |||
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All right, we should get some action now. Both combatants urr uhh contestants are now in the ring. Get this thing under way just hope neither trips over the rpm threshold. | |||
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That's funny Ray. I'll help Larry out a little bit. His thesis on this subject should have been titled "HOW TO SHOOT MOA GROUPS EASIER BY USING A RPM THRESHOLD". The important word there is "easier". | |||
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We are about ready to begin, first the introductions. Usually their weight is given. In this event pecker length will be used. | |||
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Joe I would think in your absense you could have come up with something new.....apparently not. Not telling us the incredients and % of them in your "blend" and what actual bullet design is still keeping it a secret. You remind me of the old african witch doctor who would tell the warriors; "my magic will make you bullet proof, unless you drink beer or have sex (any kind) before the battle. You must remain pure for the magic to work." The chief would order all his warriors to not drink beer or have sex before the battle so all would be bullet proof. Thus the witch doctor knew he was protected regardless of the outcome of the battle by his caveat. The after all the dead warriors were piled up in front of the British guns the witch doctor could say to the chief knowing that most of the warriors would drink beer, get laid or jerk off before the battle; "See, they were unpure, they drank beer or had sex and thus my magic could not work." Of course the surviving warriors could not admit to drinking beer or having sex before the battle even though most did of course, (including the chief). So they had to admit the magic was good even though they knew it wasn't........the witch doctor was thus protected by his caveat...... So Joe, we see you still have the "caveats".....not going to tell us the blend and not going to tell us the exact bullet. Anyone can go to the Cast Boolit Forum and see that 45 2.1's latest heavy .22 cal bullet design for ARs is plagued by the same RPM problems as any other similar cast bullet in the fast twists. He even recommends my load of RL22 for it's use now and even he doesn't claim the accuracy you claim........but then every rile you shoot gives sub moa at rediculous cast bullet velocities.....or so it seems. Got to love your BS though.....you keep at it Joe........ Larry Gibson | |||
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Ray, is there a threshold limit on that??? | |||
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Joe Show a little imagination will ya? Let's make this fun and not regurgitate all the crap you spout that no one believes anymore (except maybe gear)......I came up with the witch doctor bit.......carpetman1 came up with his threhsold lines.......actually you did come up with the blended powder and custom bullet BS but everyone expects that from you......be humorous for once ....you can do it...... Larry Gibson | |||
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Round one a feeling out round. Not much happened. There was a trip but it could not be ascertained if they tripped over a pecker or the dreaded rpm threshold. Both agree that if it was a pecker they tripped over, it was their own. There was a hermaprodite named McBroom. Picked up another hermaphrodite and took to the room. There was a terrible fight that night trying to decide who had what right to do what with what to whom. Feel the love. | |||
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Real poetic there Larry Gibson | |||
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Joe I'm thinking over whether to call or PM.....not sure I really want to listen to all your crap again........now if you could just stick to facts.........notice the witch doctor never gets into the battel and never gets shot? Maybe the WD knows he's been jerking off or drinking too much beer? Now we know Joe is a tee totaler (he told us)so.......... Larry Gibson | |||
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The crowd is really getting restless. This has not drawn the expected crowd. Maybe both are over the hill and don't get much of a draw anymore. One has came out of retirement and is not his old self. He is now shooting 1-1/2" groups. What? Not one holers--amazing. The other has moved to a warmer climate and possibly a more sedated life style. Perhaps the threshold has been crossed so much that it is worn smooth and is no longer the hazzard it once was? It is not known at this point if either had any pre-fight sex or beer. | |||
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When Elvis left the building it was big news. Now these two leaving the building to have a beer together? | |||
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Awww.... come on Ray. One can't trip over whats not there. | |||
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Same ole BS from you...... just like always. Folks, ole Larry ordered and received one of those custom molds hisself. As far as problems..... nada as a fellow Cast Boolits member came to my house with his DPMS AR-15 and his own chronograph and shot my loads. Just over MOA at 100 yards at a little over 2400 fps. Hard to beat with a 65 gr. cast boolit in an AR... now isn't it. Larry's favorite load is 4895 with a Lyman boolit...... can't do anything good with that at HV. Now, the question is why did you get a custom mold Larry??????? | |||
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45 2.1--Can't trip over what's not there? Just cause you can't see it doesn't mean it's not there. The only threshold paint that was formerly available was camouflage. Now you want to conceal something, paint something that is already invisible with camouflage and it becomes well, invisible plus. Not only can you not see it, you don't know where it is. It is not a limit and can be moved up and down and when camouflage painted, moved sideways or in an arc-- you name it possibilities are unlimited. I'm working on some blaze orange paint that will eliminate all this. I have in fact developed the paint. Problem is I can't find the threshold to paint it. | |||
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Not even on page 2 and already cancelled? Can't be. Maybe in 2016 they'll add high rpm shooting to the olympics and it'll get more interest. | |||
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Joe Yes I was refering the the M95 Mauser as Gruff was talking the 7x57......funny how some always get confused over the obvious........Gruff's bullet becomes a pretty homogenious alloyed bullet by the method he uses to make it. Also not except for the 1 lube groove and the small area above the GC the softer nose portin is solid, leaves little room for sloughing or unwanted obturation. The lino base is strong enough to handle the accelleration without unwanted obturation also....and excellent cast bullet for HV. "We both had a little mud slinging here and now I'm finished. Let's stick to the original post. If you can't add technical data, and only mud sling, then take a hike. " Well that's certainly the kettle calling the pot black! Consider all the insinuations in your 1st post and all your additional ones......same old joe......Yes, I can stick to the original post; it's full of pucky......Just like the witch doctors "magic". Larry Gibson | |||
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Why bob, you're talking to me! Quite frankly I got the mould because it is a good design. It also should perform well with RL22, a load you've got from me....that's ok. It's why I post it on the CBF, so those like ou could use it.....no magic secret crap from me like you and joe. Right after I posted it's successful use with the 225462 you started extoling it's virtues. Difference between you and me is I know what the real accuracy potential is and do not make stupid claims no one but joe believes, except maybe gear....... Bob, I've got seveal moulds you've designed. Never said you didn't know anything. I think that 22 NATO design MiHec made for us is probably about the best "heavier" .22 cal cast bullet I've seen. Remains to be seen in the shooting of course but I think it should do well in ARs giving reasonable (note that's not "outlandish accuracy" as you and joe claim) accuracy and functioning in all twist rifles (7 -12"). The heavier weight should mean reliable functioning even in the 7" twist guns while keeping the velocity/RPM down so accuracy will be reasonable. Should do very wellin the 12" twist ARs. Yes I do use 895 a lot because it works in many cartridges very well with cast bullets of heavy medium to heavy weight. I also use a lot of other powders and I've posted a lot about them (RL22 and AA4350, H4831SC, RL19, Vargot, H4198, 5744, 4227, 4759, 2400, H110, Unique, Bullsye, Tin Star ad nauseum........obviously you some sort of point there but stupidity of it overshadows anything meaningful........same old bob, same old joe.......BS as usual........ Larry Gibson BTW; think I'll "take the hike"......not because joe wants me to but because his and bob's BS isn't worth the effort........ | |||
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Larry, I think you ought to take Joe up on his offer to explain how to shoot 45 2.1's NATO bullet with the blended powder and see for yourself. He tried every trick in the book and a lot that aren't in the book to get it too shoot at HV and nothing worked until he found just the right burn rate for his system by blending powders. You can believe it or not, or you can learn how. He proved that how a particular propellant behaves within a particular system is the limiting factor for what he was doing, not alloy, not technique, not twist rate. To make it all work the POWDER was the key, he'd already done everything "right", same way he's made other rifles shoot so well, and it didn't come together until he got the burn rate exactly right. Of course it won't matter what powder you use if you don't get the rest of the system working as it should, and that requires the understanding of loading techniques you don't seem to have any genuine interest in gaining. Other than the drama being more important than facts to you, I don't know why you wouldn't be interested in learning something new. Joe might even take the time to teach you about case prep and bullet fit and a little thing you probably need to do to your 5.56 chamber for better results with auto-loaded cast bullets if you'd LISTEN for once instead of trupeting how you know it all and those who say they can do better than you are liars. I guess all that's pointless though since you already have your mind made up about what can and can't be done based only on your own efforts and have developed a formula to prove the rest of us can't, either. But whether you believe me or not, those guys CAN do what they say they do. How do I know? BECAUSE THE METHODOLOGY CAN TRANSLATE. But you'll have to ditch the 4895, Dacron, two-step M-die, Javalina Alox, and a whole lot of other things you think you know before your results will improve. Cheers, Gear | |||
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The promoters are breathing a little easier now. This thing will make page 2. | |||
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Gear Before you became a "regular" on the CBF joe claimed the same BS with cast bullets in his AR with not only the .223 but with the 6.5 Grendel. Same BS.......problem is you're falling for it......not me nor anyone else, I'm not calling joe because I've heard it all before, too many times......so has everyone else except you apparently........adios, as they say down your way....... Larry Gibson | |||
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Joe 1st of all; who the heck are to tell anyone to stay out of threads based on "negative comments"? That's a pretty bold yet stupid statement for YOU to make. Read your 1st post starting this thread. You make the inuendoes about me you can bet your ass I'm comming back at you. You want to spout your BS that's got you thrown off more forums than probably anyone then you have at it. No need to denegrate me or anyone else, just make your brag and leave it at that if you don't want me or others not to continually prove how stupid your claims really are by commenting to such in your BS threads. Larry Gibson | |||
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Well Larry….. your not that easy of a person to talk to….. even at a distance. I prefer to talk to someone who knows something....Not to someone who has to talk down to someone to make himself look good. Joe, I and several other people can do exactly what Joe has said….. and you can’t. | |||
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Probably becauese Von Gruff pushes the RPM threshold up using a correctly designed bullet that fits well, is cast well and uses a slower powder. Same as Bass Ackward and I have done with his LBT bullet and the poor 311291 45 2.1 keeps whining about. I also do that with the 311466 in 10" twists. I'm also shooting 1 1/2 - 2 moa 10 shot groups at 200 yards at 2650 fps with a .308W simply by using the correct cast bullet, the correct powder and by controlling the RPM with a 14" twist......not hard for anyone to do, no magic, no "master teaching grasshopper BS.....just proper cast bullet loading and understanding ballistics and what makes things work. Yes Von does it right, understand the RPM threshold is not a "limit" and posts exactly what he does withouut all the hocus pocus super secret I am the master and you must walk the rice paper, grasshopper crap. Von does not make up out landish claims that only he can do. The both of you (joe & bob) should take a lesson from Von Gruff. Yes I do "talk down" to both of you. You have both dug your slves so deep in a hole with your BS that it's the only way anyone CAN talk to you. Bob, I am constantly agreeing with many things you say and try to elicit a meaningful conversation with you on several threads on the CBF. I've always told everyone that you do know quite a bit about cast bullets. You have not yet responed to any of my posts there agreeing with you. You probably have me on "ignore" there. All you do is denegrate me on this forum so why should I be "easy to talk to"? Be a little more civil and open minded and we could probably learn a lot from each other. Larry Gibson | |||
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Well.... such a long spiel. First, Bass Ackward said your Lyman 311291 was completely out of spec besides being a junk mold. From the dimensions he gave he was right. Secondly, we have several people who shoot 180 gr. cast 308 Win loads above 2600 fps into less than 1 1/8 MOA, so your qualifications don't match theirs and their shooting old military rifles.... not custom barreled jobs. Thirdly, all this master and grasshopper bit is one of your taunts. I have repeatedly said several people do this, some do better with rather unlikely rifles. I would hope you can understand that finally. So clean up your language.....your only hurting yourself. Next... Your talking down to people seems to be a constant when those people don't agree with you or praise you for what you say. Its really old, get over it and act like a human. Now... your not on ignore, but I sorely wish you could control your tongue and act right. Like I said, nobody wants to listen to your diatribe. I don't like you enough to help you learn anything. Thats why you don't get help............. | |||
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