Air Gun Home :: View topic

rsterne · Moderator

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-product/331/kogels-224-5-7mm .... http://www.mauricedrummen.nl/webshop/contents/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

rsterne · Moderator

I got my sample bullets in the mail today from Sean, measured, phtographed, and weighed them, and ran them through the Border Barrels Twist Calculator.... Here are the results:

.222 cal 39.5 gr. - length 0.476" - weights varied from 39.3 - 39.8 gr. over 6 bullets....

These appear to be similar to .22LR bullets with lube in the grooves, and are the correct diameter for a rimfire barrel, and so I ran them using a 1 in 16" twist which is typical for that caliber....

The stability is between 1.5 and 2.0 from 500 fps to 1050 fps, so that would appear to be OK if you don't push them over that....

.224 cal 41.5 gr. - length 0.474" - weights varied ONLY 0.1 gr. either side of 41.5 gr. over 16 bullets - they are arranged in groups by weight in the photo below....

These are made by RWS, and Sean believes them to be a slightly bigger (0.002") version of their R-50 target bullet.... They are supposed to use a .22 Hornet barrel with a 1 in 14" twist, so that's what I used below....

The stability is between 1.5 and 2.0 from 900 to 1100 fps in the 14" twist, but when I checked them with a 16" twist, it was only 1.1 at 1100, so that would not be a fast enough twist unless you kept the velocity under about 950 fps....

.224 cal 63 gr. - length 0.660" - weight varied from 62.6 - 63.6 gr. over 8 bullets

These appear to be a cast bullet, and were not quite of the same quality as the others.... I used a 1 in 10" twist when I ran them through the calculator....

The meplat on these bullets reduces the stability at the lower velocities, you can see the flattening of the curve.... However, the stability is still between 1.6 and 1.8 for velocities from 500 fps to 1100, which is just fine....

Sean and I will be using the .224 cal 41.5 gr. RWS bullets, and they look to be a fine match with the .224 cal 1 in 14" twist liners from T.J.s which are on the way....

Bob

rsterne · Moderator

This group was just shot in Holland at 100 metres (110 yards) with a Drummen Sinner .223.... It was shot outdoors, and measures 17mm (0.67") C-T-C....

Now we know what the 41.5 gr. RWS bullets are capable of.... It's just up to us to build a rifle to make use of them....

Bob

gicos · Member

Any more testing on this one? Right down my alley.

radar · Silver Status Member

I think the only criteria for shooting straight-sided bullets out airguns, is the same as with .22 firearms. Spin them fast enough...
A faster rifling twist and/or higher velocity should work as well with an air rifle. Even .22 rimfire CB caps lose accuracy past about 25 yards, in my experience. Presumably because the typical 1:16 rimfire twist is too slow for their relatively low velocity. They seem to keep their nose first, but downrange, they begin to wobble enough to ruin good target accuracy.
cheers
Rob