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pellet experiment
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Author:  joe hickey [ Wed Oct 02, 2013 5:02 pm ]
Post subject:  pellet experiment

Just received a new order of JSB .22 and .177. Although they shot fairly well, they looked awful. A definite line from manufacture. So I took a half tin and tumbled them in a gem tumbler for a couple of hour,s. The accuracy improved considerably. I will do more test,s with group pic,s when I get a calm day. Here is a pic of the before and after tumbling. Notice the skirt on the .177. It,s rounded off inside and out. The accuracy with those pellet,s was dime size at 50 yd,s.from 1.5 inch.with my Pneuma. I just about sh**.
Image

Author:  rrdstarr [ Wed Oct 02, 2013 5:08 pm ]
Post subject:  Re: pellet experiment

Joe, what was your tumbling media? Walnut hulls? Something fairly soft I imagine?

On another topic, How are you doing on stocks this summer? I have only seen the one? Sure like seeing you post about your stocks! :D

Author:  joe hickey [ Wed Oct 02, 2013 8:31 pm ]
Post subject:  Re: pellet experiment

rrdstarr wrote:
Joe, what was your tumbling media? Walnut hulls? Something fairly soft I imagine?

On another topic, How are you doing on stocks this summer? I have only seen the one? Sure like seeing you post about your stocks! :D

I only put the pellet,s in by them selves, no grit. As far as stock,s are I've been up to my neck in working on my house and my driving job. Hopefully soon if I don't go to Alberta for the winter.

Author:  Castle02 [ Wed Oct 02, 2013 8:39 pm ]
Post subject:  Re: pellet experiment

If you come to Alberta, bring your guns and come shoot with us!!

Author:  Edmonton<500 [ Wed Oct 02, 2013 11:18 pm ]
Post subject:  Re: pellet experiment

Hope you do, Joe. Lots of us here who would love to meet you. Keep us informed.

Author:  Handyguy [ Thu Oct 03, 2013 9:47 pm ]
Post subject:  Re: pellet experiment

Castle02 wrote:
If you come to Alberta, bring your guns and come shoot with us!!


Lemme know if/when this happens, I'm itching to get out with a group and try my new 2079.

Author:  joe hickey [ Fri Oct 04, 2013 6:05 am ]
Post subject:  Re: pellet experiment

Unfortunately I'll be going out to work and the shift is from 4 AM to 9 AM and then 4 PM to 9 PM. for 28 days then 2 week,s off. Not much time between shift,s to eat, sh**, and sleep, let alone shoot. And flying with gun,s is a definite no no. But I would love to meet some of you on my day,s off. It look,s now I may not be going till Jan. According to my contact. If so, I might get a few stock,s done after the October rush at work.

Author:  peterdulux [ Fri Oct 04, 2013 9:00 pm ]
Post subject:  Re: pellet experiment

Funny. remember my extreme pellet cleaning with the case vibrator and all the stuff that came off the RWS pellets?
Well, did some shooting today and noticed that RWS H points that were cleaned were loose in the barrel and didn't group worth a crap. Unwashed H points, grouped amazingly well, as before. That was in a Diana 34 in .22 Vorteked.
Washed superpoints grouped pretty good but didn't have any unwashed to compare.

Results from my XL1100 varied with several different pellets. Hold is critical with this gun. CPHP shoot very well, but too bad the size is so inconsistent.

Going to try your idea at some point, joe. I'm going to use a very fine sand and try a certain number of pellets for certain lengths of time and see what kind of results can be had.

I think you are on to something when it comes to removing excess material from the manufacturing process that can effect pellet flight.

Author:  joe hickey [ Fri Oct 04, 2013 11:54 pm ]
Post subject:  Re: pellet experiment

peterdulux wrote:
Funny. remember my extreme pellet cleaning with the case vibrator and all the stuff that came off the RWS pellets?
Well, did some shooting today and noticed that RWS H points that were cleaned were loose in the barrel and didn't group worth a crap. Unwashed H points, grouped amazingly well, as before. That was in a Diana 34 in .22 Vorteked.
Washed superpoints grouped pretty good but didn't have any unwashed to compare.

Results from my XL1100 varied with several different pellets. Hold is critical with this gun. CPHP shoot very well, but too bad the size is so inconsistent.

Going to try your idea at some point, joe. I'm going to use a very fine sand and try a certain number of pellets for certain lengths of time and see what kind of results can be had.

I think you are on to something when it comes to removing excess material from the manufacturing process that can effect pellet flight.

More important than cleaning the debris, is polishing the rough spot,s out and smoothing out the skirt,s. I noticed the skirt,s had very irregular edges when magnified. I would not recommend using sand or grit of any kind. I tried that and the stuff got stuck/packed, inside the skirt,s. I think just the rubbing together of the pellet,s does a great job.

Author:  rsterne [ Sat Oct 05, 2013 8:25 am ]
Post subject:  Re: pellet experiment

The only reason I can see for this working is the removal of imperfections around the edge of the skirt which releases from the crown.... Just as a bad crown would cause tipping of the pellet at the moment of release from the muzzle, so would any dings on the edge of the skirt.... This is also seen on cast bullets with a full diameter cast base, where two problems arise.... incomplete filling of the mold corner, and damage from the sprue-cutter.... If you closely examine cast bullets, the edge of the base is often rounded slightly on one side, or in some other way assymetrical.... I'm thinking that this would be an argument for using cast bullets with a beveled base, or intended for a gas check, where any imperfections at the OD of the base would not be right out at boresize.... You can see that in Joe's tumbled pellets, the point of release from the crown is no longer at the back edge, it is moved forward by the radius on the back corner caused by the tumbling....

Perhaps tumbling of cast bullets is worth a try?....

I also wonder if there might be a measurable improvement in the Ballistics Coefficient with the slightly rounded back corner.... Joe, have you Chrony'd the raw vs. tumbled pellets at the muzzle and noticed any difference?.... If not, and they are faster at 25 yards, that would indicate an improvement in the BC....

Bob

Author:  Daryl [ Sat Oct 05, 2013 11:08 am ]
Post subject:  Re: pellet experiment

I suspect with pellets, as with powder burning rifle, the base is the most important surface. In a cast bullet powder burning rifle, the base of the bullet must be perfect to deliver it's best results by giving perfect delivery from the muzzle as Bob noted.

In air rifles, obviously, the nose is also of major concern - would be like casting a rifle bullet that was tapered base to nose and ended up with a loose nose, which would also cause inaccuracy due to wobble down the tube, thus off-centre delivery from induced yaw at the muzzle.

In the case, the nose must remain of sufficient size to guide the pellet, and the base must be perfect to deliver the pellet from the muzzle. In Peter's rifle, the tumbling reduced the size of the pellet to make it useless - as with powder burners, experimentation is where IT'S at.

Author:  rsterne [ Sat Oct 05, 2013 2:39 pm ]
Post subject:  Re: pellet experiment

I've got lots of cast bullets with imperfect bases (few that are perfect, in fact).... and I just happen to have a lapidary tumbler.... I'll try tumbling some for different periods of time and see how they look for a start.... after I get home from Ontario....

Bob

Author:  joe hickey [ Sat Oct 05, 2013 4:11 pm ]
Post subject:  Re: pellet experiment

After more experimenting today, I was impatient and tubled a half tin of RWS hobby,s for only ten minutes. The accuracy difference was amazing. 1/2 inch group from the tin down to one holer at 15 yds with my .177 Pneuma. I noticed immediately the skirt had no sharp or irregular edges. Maybe that,s the key. I,m going to try ten minutes with JSB,s next windless day at 50 yd,s.

Author:  mike87gt [ Sat Oct 05, 2013 4:13 pm ]
Post subject:  Re: pellet experiment

How much material gets removed from the tumbling?
Is it enough to considerably reduce the pellets width making it loose in the barrel??

Author:  joe hickey [ Sat Oct 05, 2013 8:22 pm ]
Post subject:  Re: pellet experiment

mike87gt wrote:
How much material gets removed from the tumbling?
Is it enough to considerably reduce the pellets width making it loose in the barrel??

Yes if you tumble too long. Not from material being removed but from being compacted. I accidentally forgot a batch that tumbled over night and some of them slipped about an inch down the barrel. However they still shot with greater accuracy than out of the tin ones. The idea is not to remove material. Except for the crosman,s which have a lot of loose bit,s of lead in the tin anyway, most other quality pellet,s are relatively clean. The idea is to smooth out the head,s and tail,s,. It probably wouldn't work if you tumbled say 5 pound,s of pellet,s at a time because the weight on top of the ones underneath, would likely reshape the pellet into a ball. Gently using the pellet,s own weight with about half a tin at a time is less likely to crush the pellet,s. As with the line down the side of the pellet,s from the mold,s,the outside edge of the tail, also has irregular sharp edges from the molding process. unless you look closely, you would never notice the irregular edge. I took pic,s and enlarged them and was shocked that they were accurate as they were considering how rough the skirt edge was.

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