I am curious if anyone else has the problem of pellets breaking the speed of sound with the model 48? Depending on the pellet, I get a very loud crack from the barrel of the 48. For example, using an RWS 8.2 grain pointed pellet I get the crack, but using a Kodiak 10.3 grain I get no crack. The speed of sound at 20C is somewhere in the neighborhood of 1100 fps. From the ballistic data I got from AGE, the model 48 with most pellets should be nowhere near 1100 fps. What gives?

Hello, is your gun new? If it is it may be diesling. Is there any smoke when you shoot it? I am hopefully getting my licence in the mail soon and then picking up my m48 and I hoped that an 8.5gr pellet would keep it subsonic. If your rifle is new and it is in fact diesiling, it should eventually settle down and stay subsonic. I hope I have helped.Mulby.

Yes, my gun is new. I only have approximately 300 shots through it. Also I get some smoke from the chamber after I shoot. How many shots does it normally take for the gun to settle down?

I believe that the speed of sound is 1050 fps and that the 48 is rated around the 1100 fps with lighter pellets. I just received a slightly used 48 with around 300 rounds through it, and shooting a 8.5 grain rws pointed ( can't recall exact name) I get a very nice thwack. I have only shot a few dozen rounds through this gun so far and just love it. They are highly worhth getting , even here in Canada with the licence problems. But as stated above keep shooting it and it should settle down.

R.

I have a iused 1994 Diana model 54 which I bought lately, same powerplant mechanism as th 48. I renewed the spring and washer and it sounds also like a 22 firing. It also smokes. Inaccuricy is defenetely felt, but you must know That flat headed match pellets (6.6 grain approx) are thrown away from the target since past and trans-sonic velocities apply enormous instabilities on them. The reason is trhe shock wave that needs a sharp or round head to break through. 8 grain pellets and up are prefered. Gamo pro-magnum shoot reasonably, I would guess the german equivalent (spitzkugln or dome headed) are best. The 48 - 52 -54 are great rifles, but need some knowledge and skillness which Im sure you will have.
Enjoy and act safetly.

If I am not mistaken temp,humidty,and altitude{barmetic pressure} all play a role in the speed of sound.Enough of that.My 48 {.177} cal.likes heavier pellets {Round nose} Crosman Primers @ 10.5 grs.,Beeman Ram Jets @ 9.8 grs.I shot about 2500 rounds thru it before it really started settling down,so test ,test test.I am going to try some Beeman Kodiak @10.6 grs and JSB Exact @ 10.2 grs.to see what kind of groups I can get.Good Luck and good shooting,Gary

Yes your correct on all, you've done your homework.
I love my 48. Use a heavy pellet for the mean time.

Yeah it does this for a while. First pellet I shot out of my 48 when it was new sounded like a .22 and smoked like a black powder gun. The pellet pierced a 1/4 inch sheet of plywood that I shot it at (!!!) and lodged in the garage door behind it- with the head of the pellet portruding out the ouside of the garage door. Dieseling was normal for the first 30 or so shots as well as wandering accuracy for the first 1500... Lean towards the heavy side with pellets and youll be ok. Some cracking at the start and if you lube the mechanism in a way that gets lube near the breech seal will also cause it so watch how you lube it (cocking lever etc..)

I have a 48 demo I bought from AGE. Only put less than 100 pellets so far.
The gun straightshooters.com chronied did 1077 fps with Beeman Silver Bears. I love novelty, so I ordered a small tin to amuse myself. My gun shoots hard, but no crack. I've tried RWS Meisterkugeln 8.2gr, Gamo Match 7.2gr, Beeman Black (Chinese) Wadcutters, Crosman Wadcutters 7.9gr, the new CP Hollow Points, and many heavier pellets. I haven't really tested accuracy, but I plan on using a heavier domed pellet like the CPH for general shooting. I admit, I am a bit disappointed that I haven't found a pellet that cracks from the gun.
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Dan

Maybe because it was a demo 48. How many shots goes through a gun in a 'showroom' atmosphere? I am not sure. I think the dieseling has a lot to do with it. Does your gun smoke after a shot? Straightshooters probably made sure it wasn't over lubricated. I would consider yourself lucky. That crack from the lighter pellets gets on my nerves.

as it flies from the gun to the target. The reason is that trans-sonic turbulence occurs just above and just below the speed of sound. Have a Crow Mag that is just supersonic with light pellets and you're lucky to get 8 INCH groups at 10m if you use light pellets. Just a bit heavier pellets and it's spot-on and much less "crack" when shot.

I've got a well used .177 Model 52 that still cracks the sound barrier with lighter pellets. I typically shoot 10.5 CPH through this rifle and there's no crack, but, I've got many tins of other, lighter pellets for my R7 and R9. The CPLs through the 52 sound like I'm shooting a .22 rimfire

I posted above in this thread, over two years ago, about how I was disappointed about not getting the "crack." One cold, winter, day it did break the sound barrier with Silver Bears. In warmer weather it shot CPLs a tad over 1000fps, CPHs right at 800, and Silver Bears around 1050, IIRC. I've since traded the 48. It was a powerful and accurate gun, but very harsh and I didn't want to invest in a tune kit.
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Dan (in NY)

light pellets or pellets that fit lose will gain in speed. if your rifle is 1000fps, you can cross 1100 fps. gammo has a high volcity,gold plated pellet that i have tried and it flys. in a rws34 it clover leafed at 333 feet.My friend was very happy


ps to loose may be same as dry firing---be careful

The gamo super light pellet is called the Raptor..... It is not accurate in any rifle past 20-30m (thats 60 -90 feet)...

Are you telling me you shot clover leaf groups at 333 feet?

No way hosé

Maybe 33 feet.