GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Ribbonstone on December 05, 2017, 10:12:31 PM
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Finally got ready to tests those .22 34gr. JSB Exact Jumbo Beasts (rather than just goof around with them)....and the cold front comes though. Sideways rain with really strong winds...and likely until Thurs.
A lot of reasons for a pellet to NOT SHOOT well, but most of the advice has been aimed at barrel twist rate.
Have one 22 rifle in mind for this, and it has already show it will shoot slightly longer and slightly heavier slugs well.
(http://i157.photobucket.com/albums/t50/ribbonstone/micro%20pellets/c075c383-4348-4795-9c5e-65183f82554d.jpg) (http://s157.photobucket.com/user/ribbonstone/media/micro%20pellets/c075c383-4348-4795-9c5e-65183f82554d.jpg.html)
Am thinking, if it will shoot the slug well, then it has a chance at shooting the pellet well.
If it does shoot well, then I'd rather use the pellets than the slugs(which are kind of labor intensive).
If it doesn't shoot well, don't think I can automatically blame barrel twist or pellet weight/length.
Could be the weight balance, the bearing area, diameter...but hopefully will get it's first tests tomorrow after work.
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Geez, that slug looks more like an artillery shell in .22 ;)
The pellet looks rather middle heavy; whatcha gonna be shooting it out of?
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Slug is kind of "knarly" looking...worked on getting the slug to fit a standard barrel rather than modding the barrel to work with a slug.
MrodAir M10...+820fps for the slug (have to wait and see about the pellet).
(http://i157.photobucket.com/albums/t50/ribbonstone/M10/7e8ed384-0f35-4620-8883-cf3aebd8fd07.jpg) (http://s157.photobucket.com/user/ribbonstone/media/M10/7e8ed384-0f35-4620-8883-cf3aebd8fd07.jpg.html)
Pellets nearly the same weight and are just a touch (like .003") shorter.
(http://i157.photobucket.com/albums/t50/ribbonstone/M10/c003e5e2-9052-44ca-ad9f-c62022ec5734.jpg) (http://s157.photobucket.com/user/ribbonstone/media/M10/c003e5e2-9052-44ca-ad9f-c62022ec5734.jpg.html)
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Those are cool looking slugs! Must be a good design if they shoot well! That M10 is a fine looking gun as well, and is putting out some real power!
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I have been pretty lucky with the 40g .25 BBT ... can pretty much call the fliers by how they load... really need to finish the leade... have done 4 melts and only only limited testing... just got a .249 insert to try and then with knurling... One of my .250 sizing inserts is closer to .2495 than .250(Knurling is worse) still mostly getting .75" with 2-3 in (10-12 shots) fliers out to ~1" at 50 yards
one of the things that I think might be worth trying when sending slugs out of the mildly choke barrel of the Mrods is to pull the shroud and semi float(oring or craft foam pad?) thru a barrel band like the 10's..? how is it set up on the 10..?
Do/did you move the band to try and tune for the pellets/slugs if there looks to be a harmonics prob..?
I think knurling that .249 or .248+ just might help the feeding prob on mine...
hope it is all plug and play and you do not have to slow down the pellets to find accuracy...
so yeah you find a slug that you can work with and get it working its best with the barrel... it would be great to have a pellet that ends up being plug and play at the same setting....
fingers are crossed for you.. 8) even if you do not want the work, you know you can have the independence of casting also...
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Ribbonstone,
I'm confident you are likely going to see acceptable results with the JSB Beasts.
My little shooting group now has 9 or 10 of the M10/M11 rifles. I think there is only 2 of them that have not liked the Beasts. and those 2 rifles, we haven't spent enough time with them yet to really make the determination.
My M10 (converted to M11 repeater) shoots the JSB Beast very well.
I am quite pleased with the performance.
(http://i979.photobucket.com/albums/ae274/ronsnewemailis/Airguns/beast%203_zpsi4drka52.jpg)
This is a 10 shot group at 50 yds.
(I'm pretty darn happy with this too.)
(http://i979.photobucket.com/albums/ae274/ronsnewemailis/Airguns/beast%202_zps4ru0p2wa.jpg)
I'm looking forward to seeing what yours does, and what you end up doing to the rifle to squeeze everylast drop of energy out of it ;D ;D ;D
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Be interesting to see your results.... I had zero success with the 34 gr. Beasts in a 16" twist at 885ish.... OK (but not great) at 50 yards, and lucky to hit the paper at 100.... I assume they are spiralling, but the ambient lighting would not allow me to see that....
Bob
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I believe the M10 barrel is a 20" twist.
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Bob
I had the same result with .22 LW 606x16mm barrel ( 42m acceptable 1,5MOA at 71m out of paper ) but I was shooting at lover velocity. Probably they need velocity 900-950 FPS.
Ron, probably use polygonal barrel.
Ron , how they shot at lover velocity and/or longer distances.
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Probably they need velocity 900-950 FPS.
Ron, probably use polygonal barrel.
Ron , how they shot at lover velocity and/or longer distances.
I agree that these heavy Beasts need to be going 900+ FPS to maintain any decent trajectory.
Basically the faster, the better. I've not shot them at lower velocities, and I think anything down around 800-820 would have a trajectory like a rainbow.
My barrel is a bone stock factory rifled barrel from SPA, (not a Polygonal).
As for longer distances, I am very happy with them out to 125+ yds, and I would not hesitate to take a head shot on a Coyote or Rabbit.
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That M10 is a beast !!! Ron did you get your M10 from the states ??? If not where did you buy it from, I've been seriously thinking about getting one myself (wish I had jumped on the deal Mrodair had when they still had them). If whoever has them in stock and for sale I'd be tempted to order one and hopefully it would come with both transfer ports that were included on Mrodair.
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Krale-schietsport.nl has them for not a bad price.
https://www.krale-schietsport.nl/en/spa-m10.html (https://www.krale-schietsport.nl/en/spa-m10.html)
Sounds like you can order the m11 breech and magazine from Julie and switch it out on the M10 to give multishot capability.
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That M10 is a beast !!! Ron did you get your M10 from the states ??? If not where did you buy it from, I've been seriously thinking about getting one myself (wish I had jumped on the deal Mrodair had when they still had them). If whoever has them in stock and for sale I'd be tempted to order one and hopefully it would come with both transfer ports that were included on Mrodair.
I actually found mine "used" for sale that the original owner had purchased from Mrodair.
Krale-schietsport.nl has them for not a bad price.
https://www.krale-schietsport.nl/en/spa-m10.html (https://www.krale-schietsport.nl/en/spa-m10.html)
Sounds like you can order the m11 breech and magazine from Julie and switch it out on the M10 to give multishot capability.
This is correct.
You need to order the breech, bolt, magazine, and the lower rear tube section that connects to the rear of the valve.
If you are the "tinkering type",
I would also suggest getting an additional transfer port (so that you can modify it larger if you so desire), a couple of extra mags, and maybe even an extra moderator (if you want to tinker with modifying that too.)
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My experience with pellets spiralling is that higher velocity increases the problem.... A 16" twist is plenty fast enough for gyroscopic stability, my guess is that it is too fast and producing Dynamic Instablity which causes the spiralling.... The few holes I found in the target paper were round and showed no signs of tumbling....
Bob
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Give it half an hour....should be back shortly after than. Still raining
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Will work in this rifle.
INItAL TESTS.
It is raining...it is cold for my claimate (New Orleans) so a bit of adaptation for comfort.
23yds is all I had today (to keep me in the heated shop and the traget paper out of the rain).
Mrod Air M10, aingle shot.
3-9X AO scope.
Unchanged from sighting in with the 34gr. .22 slugs (which is why the quick test groups are kind of a ping-pong match if scope adjustment).
(http://i157.photobucket.com/albums/t50/ribbonstone/M10/904e1c95-6cfa-4ecf-9d62-f3b274871cf3.jpg) (http://s157.photobucket.com/user/ribbonstone/media/M10/904e1c95-6cfa-4ecf-9d62-f3b274871cf3.jpg.html)
INITIAL VERDICT (depending on some +40 yard shooting) is that this particular rifle will shoot those 34gr. JSB pellet (at least as well as I will evern need).
YEAH...there is still a chance that they will "go stupid" past some range and go into either a "death spiral" or into a "random tumble pattern " at longer range...but I think NOT.
THese (in this reifle) earn at least a short range "pass". 1 1/8 MOA ain't so bad.
So I will:
#1. Test at longer range (once weather inporves nd I can get out to 45- 50 ytards without needing a winch to get out of the bad spots) to be sure these pelltets dont' suddenly become "stupid".
#2. Test in "media" to see if the pellet-type 34gr. pellets penetrate more test media than the @@@-heavy slugs (which tend to flip and go butt-first after a certain amount of media penetration).
#3. Already decided to order a couple-more tins.
#4. HAve to figure a really accurate/dependable way to measurer the twist rate of thaws M-10 barrel. Tight patches/ball bearing cleaning rod is just not quite good enough to tell a 1:16 twist from a 1:14.5 twist (will mention I come up with 1: 15.8 on a 5-try average).
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I measured twist rate with pellet itself . I made mark on the pellet head with permanent pen before pushing it through barrel bore.
Asian ( China and Korean ) barrel have slower spin/twist 19”-21”
https://www.gatewaytoairguns.org/GTA/index.php?topic=127317.msg1247992#msg1247992 (https://www.gatewaytoairguns.org/GTA/index.php?topic=127317.msg1247992#msg1247992)
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That's slower than normal....which would work against long pellets/slugs working well.
When I used the "tight patch on a ball-bearing cleaning rod" got numbers from 1:16 to 1:17.2. Figured the variation was due to some slippage....but nothing says China has to use the same barrels from the same makers, so no promise all the barrels have the same twist.
I'll have to debarrel it to be able to get at both ends.
Cut a slot across the nose of a slug and fill it with white out so I can see it.
Grease pencil mark on the barrel in line with the slot.
Mark the rod at contact, push it from the rear, and then re-mark the rod once it's made a revolution.
WHY NO NEW (longer range) TESTS:
Normally, I'll give them a try at 20-25 yards. If new pellets shoot like "carp" at that range, going father isn't going to be productive.
If they shoot well at 20-25 yards, they deserve a test at 40-50 yards.
That's not happening real soon.
Can count the times (6) I've made a snowman in New Orleans. First was in 1958. According to the records, have had actual accumulations of snow 18 times from 1853-2017.
Don't think we'll see enough accumulation to make a snowman tonight....but it's been raining for two days and there is no way I can get out to where I can get to 50 yards until Saturday (even with a Jeep).
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The barrel (M-10) was taken off and twist rate measured as I mentioned above 3 times. Not exact, but only a few 1/10ths between measurements, so using the average of the 3m comes out to be 1:15.8 inches (which, in the metric world where the barrels were made, is very close to 1:400MM).
That also agrees closely with the "tight-patch-on-a-ball-bearing-rod" method of twist measurement.
Not saying other measurements of other barrels is "wrong"...likely there are more than one supplier of barrel blanks...but at least I'm sure this one's twist is within 5% of 1:15.8" (or 1: 400mm).
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Likely to gnaw on this bone for awhile.
Even with the weather conditions against me, have been working/thinking about it.
First snows in this area for 9 years..this is not the day to head out into the boon-docks....so no longer range shooting.
Still wanted to get an idea of these pellets in other rifles, so tested EVERY .22 PCP's in the safe(s).
So for the last couple of afternoons/evenings have done pile of shooting...but not really enough with each rifle for it be definative( I'm sticking to 4 5-shot groups as averages being definative...anything less being "suggestive").
A "ship" load of shot targets:
\(http://i157.photobucket.com/albums/t50/ribbonstone/c8c1da05-1b06-451a-94b2-b0abbff1127d.jpg) (http://s157.photobucket.com/user/ribbonstone/media/c8c1da05-1b06-451a-94b2-b0abbff1127d.jpg.html)
I just shot one or two 5-shot groups (OK..at one, I stopped at 3 shots). Not enough to really make a statement, but enough to know if there was any hope for the 34gr. at lower speeds).
Besides...it's cold..dim/dark....snowing/sleeting...wind cross wise and really gusty...not the condtions to do any kind of exacting test.
Unless I break out the co2's (not likely in this weather) or the springers (also not likely with 34gr. pellets), I've shot all the .22 bores.
Tested .22 PCP rifles:
AA s200: Set as a 12 foot pound gun. Managed 12.9 with the heavy weights, but that's only 413fps. Hopeless accuracy with the 34gr. pellets
P-rod carbine with LW barrel: Set as a 15 foot pound carbine. Managed just at 15 foot pounds (446fps) with the heavy weights. Not hopeless, but at least 6-7 varuous pellets shoot better.
MrodAir PCP Pistol (turned carbine): Also set as a 15 foot pound carbine, The 34gr. broughtthat up to 15.4 (451fps), but the accuracy was totally usless.
FDPCP : Set up for 19.5-20 foot pounds. Managed 23.9 foot pounds (563fps) with the 34gr, but another hopeless case for accuracy.
Discovery: Set up as a 19.5-20 foot pound rifle. After the 3rd shot, gave up on the 34gr. No velocity/energy numbers.
Beeman Chief: Set up as a 25 foot pound rifle. With the 34gr., managed 27.6 foot pounds (605fps) wiuth the 34gr. Accuracy good enough to retest at longer range.
BAM 51: Set up as a 34.2 foot pound rifle (18gr. @ 925fps). Managed 713fps with 34gr. (38.4 foot pounds) and shot well enough to get a re-shoot at longer range.
Previously tested MrodAir M10: set up as a 48.3 foot pound rifle (25.4 @ 925fps), managed 841fps with the 34gr. (53.4 foot pounds) and shot really well.
So...considering how these really heavy .22 pellets have reacted so far, does seem like something in the 620-700fps are wouds be a minimum requirement (still a decent energy rating at 29-37 foot pounds).
So...if I were to make assumptions
1. The accuracy didn't get interresting until +600fps (lets say 27 foot pounds).
2. IF the twist is as close a I've measured, then I'd lay off using 34gr. pellets except in the already powerful .22's. They don't seem to be a sollution for low speed/moderate power .22 PCP's.
3. If the twist rate of these barrels is close (and they seem to be reasonably close), then stability is on the edge with 1:16(ish) barrel twists.
4. Likely it's rotational velocity rather than forward velocity that determins stability. A nice way of saying that rotational decaly is slower than BC decay. So likely the 34gr. pellet that starts out at 840fps will still be stable down range at well under 600fps becasue the "spin" of the pellet decays slower.
So If I had to guess before shooting...I'd guess the M-10 using these pellets would stay stable and useful to 70-75 yards.
But the test of that will have to wait a day or two...will let it stop snowing/sl;eeting and the roads to de-ice before I find out.
FUTURE TESTS:
#1. Will bring out the Chief, BAm 51, and M-10 out to 45-50 yard targets and test again....the other .22 PCP's (lower speed) are't going to self-healand suddenly shot better with more distance.
#2. Can see a head-to-head, .22 vs. .25 JSB test coming...and after all, why would JSB make the same weight in .22 and .25 if they were not INVITING a head-to-head test?
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Thanks for sharing! Very interesting, looking forward to further results!
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Interesting results.... will be watching for the future tests as well....
Bob
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Sometimes I back up and take a realistic view of what my airgunning needs really are\.
Doesn't really included +50 foot pound .22's.
But sometimes I just want to puch things a little to "see what I can see" even if it is not something real useful to me.
Think I'd likely find a lot more uses for an 18gr. @ 925fps than a 34gr. @ 640fps....but it doesn't seem to stop me from experimenting/testing.
To be honest with myself, I don't really have a burning need for +50 foot pound airrifle for anything....once I get to that level (not being a convicted felon and not living ina firearm repressive state), usually just opt for the powder burner.
Can see where airguns get counter-productive. The plus for me is high accuracy, low power, low noise. THOSES are the things that let me (1) shoot at home and (2) shoot on land that the owner has closed to firearms use.
Give those up, and I'll just burn powder.
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Yeah, a lot of what I do is just to see "what happens".... *LOL*.... If I need 70 FPE its a lot easier with a .25 than a .22 (even though I have a .22 that will do that).... and if I need 100 FPE, it's easier to reach for a .30 cal than push the .25 using bullets....
but that doesn't stop me from playing.... *grin*....
Bob