.22 RD Monster's Instability Issues

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I have a .22 R3 EdGun Long that loves the RD Monsters. Shoots them at 925 fps. This gun incouraged me to sell my .22 Red Wolf HP because I was slightly more accurate at 75 & 100 yard with this Eddy. The EdGun has a LW 1:16 twist.
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Have you taken the RD monsters past 100 yards? Say 150+? 

Be interesting to see if there is a relationship between stability and velocity. Just because it shoots good at 100 yards with a gun tuned for that, doesn't mean it will shoot good at 150.

What gets me is that it will shoot excellent groups out of my gun at 10m, but at 120+ it's like a shotgun. So in my case it's leaving the barrel stabilized, but at some point between 10m and 120 yards it destabilizes. 
 
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No, I have never shot for groups past 100 yards with a pellet gun. I compete to 100 yards thus that is my max that I need to test and practice at. 

At some point, depending on your barrel's twist rate and the projectile's BC, the spin rate will reach a destabilized point as it degrades. The spin rate degrades just as your velocity degrades once it leaves your barrel. This degradation is caused by the atmospheric conditions that the projectile is fighting through and influenced by as it travels. At what distance this happens is a variable that you must test to know. There is no magic distance that all projectiles and guns fall under. If you shot a projectile in a perfect vacuum and in a condition with no gravity to influence it, it would travel perfectly forever without spin rate or velocity ever changing.
 
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If you can see that the pellet is stable out to 100 yards, it more than likely will remain stable until it drops from the sky. At least that's been my experience. To check this, just shoot your gun at an upward angle with a background that allows you to see the pellet's flight, or record it if you have that ability. Watch its flight as it arcs and then drops. That won't give you a "stable distance", but it will let you know if it destabilizes at all. With a .22 JSB 18.1 grain from my Cricket, it just doesn't destabilize. Neither does the .30 JSB 44.75 grain from my FX Bobcat. I haven't tried this with other guns, but I suspect that the .25 JSB 25.4 grain remains stable from my .25 Vulcan Tactic since I watched the flight to a ground squirrel at 200 yards, no instability. So, what is my point? I think that once your pellet remains stable to a certain point (could be 50 yards, could be 75 or 100 yards), it will remain stable, period, because diabolo pellets are drag stabilized, not spin stabilized. IMHO.
 
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If you can see that the pellet is stable out to 100 yards, it more than likely will remain stable until it drops from the sky. At least that's been my experience. To check this, just shoot your gun at an upward angle with a background that allows you to see the pellet's flight, or record it if you have that ability. Watch its flight as it arcs and then drops. That won't give you a "stable distance", but it will let you know if it destabilizes at all. With a .22 JSB 18.1 grain from my Cricket, it just doesn't destabilize. Neither does the .30 JSB 44.75 grain from my FX Bobcat. I haven't tried this with other guns, but I suspect that the .25 JSB 25.4 grain remains stable from my .25 Vulcan Tactic since I watched the flight to a ground squirrel at 200 yards, no instability. So, what is my point? I think that once your pellet remains stable to a certain point (could be 50 yards, could be 75 or 100 yards), it will remain stable, period, because diabolo pellets are drag stabilized, not spin stabilized. IMHO.
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What I believe you are explaining is, in your experience, the .22 18.1gr, .25 25.39 & .30 44.75gr remain stable to a distance of 1) as far as you can see them through your scope 2) they hit something (target or otherwise) or 3) they crash to the dirt. You mentioned that diabolo pellets are drag stabilized.

So do you think that the diabolo pellet would be stable without any spin rate as long as they are under drag? I would say no. If you shot a pellet straight up into the air (please don't), it would eventually stop its progress upward and reverse directions back to earth. It would then begin to experience drag again as the gravitational pull speeds it up. By this time, I would say that the spin rate was dead and wouldn't believe that the pellet would be stable on its way back down even under drag.


 
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Yes, that's what I've experienced. If you read some of Harry (@Yrrah) papers, he explains why the pellet has to have spin initially, but later on it really doesn't matter much. I'll take a look for those explanations, or maybe he can chime in here, since he's the true expert on all of this, certainly not me. I'm pretty much a Newbie, only been shooting high powered air rifles for a little over two years. I think Matt also did a video explaining the difference between slugs or bullets, and diabolo pellets. And like Matt explains, and as demonstrated in Ted's videos, you can certainly OVERSPIN diabolo pellets to the point they become unstable...
 
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Matt says that you only need to spin a diabolo pellet to stabilize it as it leaves the barrel. This is because the air behind the pellet is moving faster than the pellet as is leaves the muzzle. This faster moving air would make the diabolo pellet reverse if it weren’t spinning. He says that once the pellet is away from the barrel and faster moving air, it no longer has to spin as the diabolo design is self stabilizing. 

I suppose if this is an absolute truth, due to the RD Monsters not having as much of a waist and flared skirt, it would need to spin stabilize as these aren't a classic diabolo style. 

I don't know but I do believe that spin stabilization plays a larger role for a diabolo pellet than Matt does. I may be wrong.
 
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Interesting conversation.

I just took my 18 grain pellets out to 215 (4" circle plate), 237 (6" circle plate) and at 273 yards (8" circle plate) - hits at all distances and very predictable flight when the wind is behaving. 

I'll play around more with the RD monsters. Everyone seems to say that you need speed to launch the RD monsters properly - if that's the case, then there is a velocity where they will destabilize.

Zx10wall - I agree that there is also a component of twist rate that is coming into play. I bet a faster twist would stabilize the pellet better at slower velocities - much like a traditional bullet. Not much I can do about that, unless I get a new barrel.
 
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Interesting conversation.

I just took my 18 grain pellets out to 215 (4" circle plate), 237 (6" circle plate) and at 273 yards (8" circle plate) - hits at all distances and very predictable flight when the wind is behaving. 

I'll play around more with the RD monsters. Everyone seems to say that you need speed to launch the RD monsters properly - if that's the case, then there is a velocity where they will destabilize.

Zx10wall - I agree that there is also a component of twist rate that is coming into play. I bet a faster twist would stabilize the pellet better at slower velocities - much like a traditional bullet. Not much I can do about that, unless I get a new barrel.
 
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@kthomas - damn, that's some serious distance! What's the holdover at 273 yards, about 18 feet? To get that kind of consistency with such a large drop is very impressive...
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Total elevation required is around ~25-26 mils. I dial the total 10 mils my scope has then have to holdover the rest. The reticle only has 10 mils of holdover, so I can only estimate that it's 15-16 mils holdover (on top of the 10 mils dialed).
 
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I've had pretty good luck with the .22 RD Monsters in my PT Cricket. Tit for tat with the 18.1 gr at 55yds.

I'm getting around 1.5" at 100 yds with RDM's with 1.2" being my best at 100 so far.

With 18 gr I always have a flyer that messes it up at 100 mark w? I would assume the lightest of breeze could affect it at that distance?

100 yds is my limit with most of my shooting being inside 60 yds.

Derrick tuned my Cricket and he had it shooting the RD's at 885 fps with my 17.5" barrel. Not sure what he got with the 18's?

I ran it across my chrony and it's giving me 894 fps with RD's and 994 with 18's. Could be the difference between our chrony's ? Also he's in Texas and I'm in NC.

https://www.airgunnation.com/topic/power-tuned-22-cricket-pup/

I'll pass on that 200 yd shooting. I'd have to completely redo my scope set up to even attempt it. I'm using between 8 and 9 moa holdover at 100 yds with Sightron on 30 power as I have everything I shoot here at the house zeroed for 28 yds, so I'm using holdover for the 50 yd shots as well. About 2 moa at 55 yds

Best of luck with your quest for accuracy!

Peace and Pellet Grease

Fuss








 
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An interesting fact on spin rate. The further the pellet travels the higher the spin rate per unit/distance traveled. This is because the velocity of the pellet drops very quickly. The spin rate is also dropping but at a much slower rate. 

I think this has something to do with why the RD monsters stay stable when shot at those high velocities and stay stable at longer distances. The RedWolf which shoots them particularly well has a 1:16 twist rate and you still need to shoot them around 930fps to have them stable

The new heavy pellets like the DR monsters and the King Heavies do seem to have a smaller sweet spot in regard to spin rate and velocity than the original diablo pellets




 
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The Monster Redesigned is almost becoming a slug, rather than a pellet. So, regulator pellet stability does not 100% apply. You need either speed or a higher twist rate to keep them stable longer distances. Once is slows, the longer pellets starts pointing downward and the top of the skirt get hit by wind drag, then starts the nose to wobble. There will always be a range were these pellets destabilize. In order to extend this range they have to be really shot fast. 

These are just my opinions, and observations. Hope they help.
 
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The Monster Redesigned is almost becoming a slug, rather than a pellet. So, regulator pellet stability does not 100% apply. You need either speed or a higher twist rate to keep them stable longer distances. Once is slows, the longer pellets starts pointing downward and the top of the skirt get hit by wind drag, then starts the nose to wobble. There will always be a range were these pellets destabilize. In order to extend this range they have to be really shot fast. 

These are just my opinions, and observations. Hope they help.
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What's interesting from my testing at 273 yards is that neither the 18 grain Diabolos nor any of the NSA slugs I've tested (23 to 33 grain) lose stability at that distance. Yet the RD monsters leave the barrel stabilized (based on testing at 10m) yet become unstable somewhere to 120 yards (extremely erratic at 120 yards). 

So something is certainly going on with the RD monsters, that doesn't happen to slugs or regular Diabolo pellets.
 
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Monster RD's are long with a higher BC. The reason most pellets fly well is because they have a poor bc. A pellets drag is always pointing them in the correct direction. Slugs slip through the air untouched because of their much, much higher bc. If the monsters had a lower bc they would travel more stable as they fall. If Monsters RD had a bc like a slug, the air turbulence would not hit them as hard as they fall, therefore travel more stable at distance. 

This is just the way I see it. I could be wrong. Let me know.
 
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