Anyone shooting .20 cal here?

[oldpro]

 The 20 cal is new to me I just started shooting it in the Raptor and all I can say is WOW! It cuts the wind better than any bore size I have ever tried and doesnt really care about pellet speed it shoots great from 800 and below to 980 fps.

[Tonykarter]

I last shot the .20 in a custom barrel for the SynRod and loved the caliber.  Those two .20 vids on your other thread just blew me away.   Such precision, and in the wind no less!  A Raptor in .20 is in my future.

[gendoc]

i know some of you here wont believe this, and i dont care....
 but my shinsung career-II 707 .20
puts the jsb 13.73gr pellets in one hole within ctc <1/4" @ 35yrds averaging 1096fps for a 9 shot mag.
who ever said that a pellet looses stability when over 930fps needs to get real gun......

[BackStop]

i know some of you here wont believe this, and i dont care....
 but my shinsung career-II 707 .20
puts the jsb 13.73gr pellets in one hole within ctc <1/4" @ 35yrds averaging 1096fps for a 9 shot mag.
who ever said that a pellet looses stability when over 930fps needs to get real gun......

I am curious if it is the caliber or the pellet design?

If the caliber, then why does .20 do better than .177 or .22?

Or, is it something else going on with the .20 air guns?   Barrel twist, etc, etc, etc?

Thanks!

[Ribbonstone]

At one time,ran 6 5mm's....springer, co2,HPA, and PCP.

Am down to 4..one springer, one co2, and 2X PCP.


5mm does NOTHING better...I still like the caliber, but doen't see it as really anything but an "almost" caliber.Better than .177 (at least in PCP's) but not as good as .22.

(truthfully...considering today's .25 PCP's...can think of both the 5mm and the .22 as "middle calibers"  that are a compromise.)

That seems harsh....and from a guy who actually LIKES the caliber...but I don't fool myself into thinking it's really better.

Doesn't have to be "better" to like them....just have to like the caliber. 


The old Sumatra 2500 can manage 53 foot pounds with 23gr. Sam Yangpellets (more like 1030fps max)...but I am one of the ones that find the good accurcy of the 13.7gr. JSB's is kind of lost past 920/950fps.

[BackStop]

At one time,ran 6 5mm's....springer, co2,HPA, and PCP.

Am down to 4..one springer, one co2, and 2X PCP.


5mm does NOTHING better...I still like the caliber, but doen't see it as really anything but an "almost" caliber.Better than .177 (at least in PCP's) but not as good as .22.

(truthfully...considering today's .25 PCP's...can think of both the 5mm and the .22 as "middle calibers"  that are a compromise.)

That seems harsh....and from a guy who actually LIKES the caliber...but I don't fool myself into thinking it's really better.

Doesn't have to be "better" to like them....just have to like the caliber. 


The old Sumatra 2500 can manage 53 foot pounds with 23gr. Sam Yangpellets (more like 1030fps max)...but I am one of the ones that find the good accurcy of the 13.7gr. JSB's is kind of lost past 920/950fps.

Thanks for the honest assessment.   I have read some posts from .20 zealots that make it seem that the .20 does everything better, but nobody ever delineates exactly WHY that would be.

Nothing against the caliber except for lack of much choice in pellets and the cost.

Thanks again!

[Ribbonstone]

For me,the two PCP's have been revived by the 15.9gr. JSB.

Pretty much best accuracy at something like 900-950fps (lets call it 925). Do keep a stash of 23gr. Eun Jin 5mm pellets for the Sumatra(nothing else is going to really stand up to full-power +50foot pound tunes).

'Better"...nope, you won't find a logical/data based logic in that....although some people hold that the 5mm is better by way of belief rather than proof.

SUBJECTIVELY: it can see m better (until you do a head to head test).
OBJECTIVELY: The 5mm is a "between" caliber that can be wonderful in one of the moderate power rifles....but there ain't many of those middle-piddle rifles around.


My favorite 5mm runs about 27 foot pounds:

DSCN2300 by Robert Dean, on Flickr

Which means it gets about 16gr. at 875fps.

That could be by way of a hot rod .177 rifle with JSB 16.2gr....or a typical .22 PCP with 15.9gr. JSB's.....or with the 5mm 15.9gr. JSB's. ...which pretty much puts it in the middle of BC/Trajectory/windage vs. pellet area.

[gendoc]

thats great, my favorite runs @ 36.6fpe, but can deliver 45fpe within 3/8" @
35yrds.
i have it backed down for one hole groups

[Ribbonstone]

Liked the 5mm "back when" (like back when the Sheridan was made and when Beeman was "pimping" it).

Then it went away.HW kept it somewhat alive (from what I read, that was a personal preference) for several years.

Then,Werbley gave the 5mm a promotional try....but right aver that promo,Crosamn stopped making 14.3gr. Cps...so th3e Webley tinned versions evaporated...and their 5mm (through HAtsan at that time) PCP/Springer line evaporated.

Lets face it,for old guys,if you liked the Sheridan "C", they you had to like the 5mm as you had no choice...and for some of us old guys, that kind of carried over.



Old hunting buddy passes away, and I end up with like 18-20 500 count tins of 5mm pellets....so I pretty much HAD to get a couple of 5mm's to use up this "bonanza" of free-pellets.


Which to this day, I'm still using some of them....which is why one of the faster HPA rifles got reconverted to co2.   Would shoot one type of pellet well at 600fps that the HPA version would NOT shoot at 750fps (even though the barrel and e3erything but the HPA bottle is the same).


MAYBE in another 2500-2750 shots, I'll use up the last of those old pellets and re-re-convert the 12 foot pound co2 QB back to HPA.  I saved all the HPA "guts" so wit would be a simple swap-out.

As much as I like thr 5mm...I'd not buy one new unless you had a "carp" load of 5mm pelletsor unless you were really dedicated to a choice of 3 pellets.

(it would be like a lottery to see if any of the 3 shot well).

The ONLY pellets really worth trying are:

20(ish)gr. H&N FTT.  They won't  likelywork in a PCP shooting them really fast (like over 900fps).

13.5-13.7gr. (sem like they got lighter as time whent on) JSB's.  Pretty much the standard pellet of a 5mm PCP.  About the same velocity limit in the ones I've tired...maybe 935-950fps.
15.9gr. JSB's (the newset issue pelle3ts)can stand the same speeds, which earns a really good energy for a 5mm.


Do I think the 5mm is some kind of magically-better?

Nope...it's a 5mm,and if you like the calibert...then it's"better".If you don't like the odd-ball caliber,then it "aint".

[subscriber]

who ever said that a pellet looses stability when over 930fps needs to get real gun

If you have an airgun that applies enough pressure to the base of the pellet, the skirt flares out and the "pellet" becomes a cylindrical hollow base slug.  Perhaps such distortion is the source for your better than predicted results.  Or, you are assuming that loss of stability means poor short or medium range performance; when in fact, it is at longer ranges that the instability appears:

There are many airguns that overspeed diabolo pellets, resulting in "instability".  The "instability" presents as spiraling at ranges over 50 yards; due to too high a spin speed, retained after the initial high forward velocity has been scrubbed off by air resistance.  Then, the gyro and drag stability fight each other, resulting in precession of the pellet:






Try your Korean cannon at 75 yards and report back to us...

[gendoc]

i dont intend to shoot past the ability of the "cannon"
it does well hunting squirrels in the swamp.

[Ribbonstone]

HAsn't gone full cylinder shaped...although I have seen that in a captured/springer diesel shot...but enough deforation/obruation to count.



Odd thing is that I don't think the pressure itself was higher...lower sped was a short "blip" of 3K air, high pseed was a loing "burrrrp" of 3K pressure....so a volume/duration thing rather than a peak pressure thing?

[BackStop]

HAsn't gone full cylinder shaped...although I have seen that in a captured/springer diesel shot...but enough deforation/obruation to count.



Odd thing is that I don't think the pressure itself was higher...lower sped was a short "blip" of 3K air, high pseed was a loing "burrrrp" of 3K pressure....so a volume/duration thing rather than a peak pressure thing?

That makes sense.   Think about blowing up a balloon.   You have to have volume, not just pressure.

[subscriber]

Thanks for the pics, Ribbonstone.

It takes a certain pressure to create a certain deformation.  The deformation is stress relieving the system.   Stated another way, the lead cup keeps blowing out, until its unsupported span bearing the pressure, is short enough for the material stress to drop down to below its yield point.

A short valve opening time, with air flowing through a restricted transfer port might not actually apply the same peak pressure to the pellet. Consider that the pellet is free to start moving before pressure behind it reaches 3000 PSI, and it becomes easier to see how a long blast at 3000 PSI can exceed a short one, in terms of the real peak pressure the pellet sees.   I think this is an area where springers develop and apply peak pressure directly to the pellet, that is higher than what PCPs typically do, simply due to the abruptness of springer pistons stopping on the air in front of them.

Deformation of the pellet would also take a finite, although very short amount of time.  If the time is too short, I can see that the deformation might nor be "complete".  Then short valve dwell might behave like hitting the pellets with a light hammer at the same speed, as hitting it with a heavier hammer (longer valve dwell)...

[subscriber]

Think about blowing up a balloon.   You have to have volume, not just pressure.

That is an interesting thought; that the added volume in the base of the blown out pellet is enough to drop the system pressure.  I was thinking the same thing; except that the added volume was the pellet having moved pellet length down the barrel.

That said, if the valve closed with the pellet 25% down the barrel VS 50%, surely in both cases the pellet saw the same peak pressure; when the pellet was right close to the breech?

[Motorhead]

Nothing but .20 for FT work, even have my Daystate Airwolf converted to .20 which shoots at substantially higher power just as well.

[BackStop]

Think about blowing up a balloon.   You have to have volume, not just pressure.

That is an interesting thought; that the added volume in the base of the blown out pellet is enough to drop the system pressure.  I was thinking the same thing; except that the added volume was the pellet having moved pellet length down the barrel.

That said, if the valve closed with the pellet 25% down the barrel VS 50%, surely in both cases the pellet saw the same peak pressure; when the pellet was right close to the breech?

I am thinking volume before expansion of the air.   I would think it takes a little time for the air to expand and it takes more air to expand enough to get to peak pressure.

A short blip of high pressure air simply doesn't provide enough volume to reach peak pressure behind the pellet which also explains the lower FPS along with the smaller bearing area.

At least that is how I think about it.   It simplifies it enough for me to understand.

[subscriber]

A short blip of high pressure air simply doesn't provide enough volume to reach peak pressure behind the pellet.

Makes sense, if the transfer port and chamber behind the pellet have significant volume.

[BackStop]

A short blip of high pressure air simply doesn't provide enough volume to reach peak pressure behind the pellet.

Makes sense, if the transfer port and chamber behind the pellet have significant volume.

As I said, volume of air is key.  Not just pressure.

[Franklink]

I've got a Veteran in .22 @ right under 20fpe. JSB 13.43.

I've got a USFT in.177 @ right under 20fpe. Jsb 10.34

I'll soon have a Raptor in .20 that can be setup for right under 20fpe.  JSB 13.73.

I know the first two are very accurate. Travis's vids sure make a compelling argument for the .20 as well. 

I'll wait for a nice windy day and shoot groups with all three to see how much wind drift each caliber experiences. With three very accurate guns at the same power but different caliber, should be interesting.

The most fair comparison will be between the Veteran and the Raptor as pellet weights will be very close there. They also both have traditionally rifled barrels. The .177 in the mix shoots best with 10.34gr and has a poly barrel so it won't quite be apples to apples. Still should be fun and possibly informative.