New Pellets in Holland

[rsterne]

The latest rage in the Netherlands seems to be pellets that are virtually identical to a .22LR bullet, fired from a .224 (.223"?) barrel.... They are reportedly made by RWS and weigh 41.5 gr. but I can't find them on the RWS website.... I've seen photos, and they definitely look like .22LR bullets, right down to the hollow base and smaller diameter where they would sit in the case.... They are 0.472" long, and seem to like a 15" twist....

http://www.airguns.nl/en/shop-produc...gels-224-5-7mm .... http://www.mauricedrummen.nl/webshop...s/nl/d294.html

They are also supposed to be available in a 64.5 gr. but I couldn't find them on that website.... The heavier, longer bullet needs about a 9" twist.... The 41.5 gr. bullet took all the top spots in a rainy, windy 100M benchrest competition in the Netherlands today.... so perhaps somebody has figured out how to make a non-waisted pellet work in airguns.... They are reportedly using high subsonic velocities for both bullets....

Bob

[SeanMP]

Looks like a project Bob

I'm game if you want to split a 1000 lot. I have no idea what 85 Dutch Marks equals.

It certainly makes sense. Small Bore 50m is high subsonic velocities using a 40-41 gr bullet using a typical 16" twist. Maybe it is as simple as velocity and twist.

Eric......We need barrels

[SeanMP]

sorry Euro's

works out to $106 CAD

[rsterne]

In case you don't have the information.... here are the BCs for Sierra .22 rimfire bullets at three velocity ranges....

http://www.exteriorballistics.com/eb.../22rimfire.cfm

Looks like a BC of about 0.17 for a 41.5 gr bullet with a slightly bigger diameter would be a good guess between 905 and 1047 fps.... Starting at 1000 fps (92 FPE) it would retain nearly 80 FPE at 100 yards.... With a 50 yard zero, it would be about 1/2" high at 30-35 yards and only 8" low at 100.... Wind drift in a 10 mph crosswind at 100 yards would be only 2"....

Bob

[SeanMP]

The idea is not fully baked yet Bob but the concept is to have two modular blocks.

The top block would as usual carry the bolt and be the breech socket, like your Hayabusa picture

The bottom block would be the valve body and would carry the hammer, spring , RVA. The forward end of this block would be threaded to accept the tube or paintball adapter. So far so good but I need a brilliant solution for securing the valve return spring.

These two blocks would be held together by 6 fine socket screws and the TP would be sealed by an Oring laying in a seal groove machined in one of the halves. The idea here is I would then have no restriction on the size of the ports and a rifle could be retuned by changing out the lower module.

Once the upper and lower were mated then another block could be added to the front containing the regulator (I ripped off this idea from Anschutz) Then the original threaded section becomes reservoir. And the added block is now where the tube or adapter screws on.

The reason I'm trying to work this out are to simplify. I've eliminated a separate valve body and all associated retaining screws and seals. I can change a stem or stem return spring by unscrewing a tube. I can reprofile the gun entirely by swapping a bottom or top module.

[rsterne]

I've been researching the Ballistics Coefficients for .22LR 40 gr. bullets today.... Depending on manufacturer and velocity, I've found values from a low of about 0.092 to a high of 0.158 for the subsonic, and from a low of 0.104 to a high of 0.141 for the supersonic rounds.... The we have the Sierra chart, which looks more mathematically calculated than measured, which says subsonic 40 gr. has a BC of 0.169, and supersonic is 0.145.... If I throw out the few high and low ones, the range is a lot narrower, subsonic runs about 0.125 to 0.150, and supersonic from 0.120 to 0.140.... When you consider how similar in shape the .22LR bullet is from brand to brand, I'm surprised the variation is that wide.... However, what does this mean for a rifle shooting 1000 fps, sighted in at 42.5 yards (for a 1/2" kill zone) in terms of the drop and wind drift (10 mph crosswind) at 100 yards?....

BC of 0.090 - drop at 100 yards = 9.43" - drift at 100 yards = 3.85"
BC 0.100 - drop 9.27" - drift 3.45"
BC 0.110 - drop 9.15 - drift 3.12"
BC 0.120 - drop 9.04" - drift 2.86"
BC 0.130 - drop 8.96" - drift 2.63"
BC 0.140 - drop 8.88 - drift 2.44"
BC 0.150 - drop 8.82" - drift 2.27"
BC 0.160 - drop 8.76" - drift 2.12"

Compare this with a .25 cal 15.4 gr. JSB King at the same velocity (what the Condor guys shoot)....

BC 0.034 - drop 12.31" - drift 11.04"

Comparing the most probable BC for the subsonic .22LR bullet of 0.140 to the .25 cal JSB King, the drop is 3.43" less (significant, but not crucial), but the wind drift is a staggering 8.6" less (ie only about 1/5th as much).... THAT shows why this is the preferred round for 100 yd outdoor benchrest....

Bob

[SeanMP]

Here is a link to to that outburst
http://www.airgunforum.ca/forums/topic41817-30.html

Either way you are correct we don't need or want any cross forum drama

[rsterne]

I'm tempted, Sean.... TJ's make a 0.224" groove (0.219" land) with a 1 in 14" twist, 6 land, and a 1/2" OD.... For a 24" length they should be $102 US each plus shipping, according to my last price list.... I ran the numbers through the Border Barrels Twist Calculator.... http://www.border-barrels.com/barrel_twist.htm .... using 0.472" for the bullet length (and using pure lead) and estimating the nose length and base diameter as 0.20".... and it says the Stability Factor in a 14" twist would be 1.5 at 1050 fps and 2.0 at 900.... pretty much ideal....

Tell you what.... you buy the bullets, I'll get two barrels, and we'll square up, if necessary, after all the shipping is looked after.... Whaddya say?....

Bob

[SeanMP]

How about one of each
one .223 / 16
one .224/14

And compare notes.

I have an order of those projectiles in the shopping cart I just need my Dutch coworker to help me checkout.

[rsterne]

Sounds like a plan.... You want me to order them?.... I'm thinking you are the chambering expert, though.... I can pay for them and have them shipped to you?.... Let me know....

EDIT: May have another source for the RWS pellets - sent an email....

Bob