Problems with JSB Exact Jumbo Diabolo.

[k-harr26]

Sorry for the long read. Over the last yr my wife and I started shooting .22cal pcp air rifles. We purchased several types and brands of pellets. My gun seemed to prefer the JSB Jumbo 15,89gr and hers the JSB Jumbo RS and the Jumbo. So here's what's going on. I purchase several new tins of the JSB Jumbos which have been on back order for awhile and found neither of our guns shoot the new Jumbo 15,89gr very well. 2 tins have some damage to the tins and several of the pellets are damaged as well. So today I did a little testing. I pulled 10 random pellets from each of the undamaged tins, weighed them, inspected them, chronograph and shot 5 from each can. 25yrd bench rest. I also did the same from 2 type of Crosman premier pellets and the JSB Jumbo RS. I feel there is a problem with the new pellets.

Here are the results and some photos. 

JSB Jumbo 15,89gr

80 samples (10 from each tin) 16 pellets damaged, weights vary from 15.6gr -16.3gr. 662- 685fps targets #1-8 (all 4 corner targets)

JSB Jumbo RS 13,43gr

10 samples, 0 damaged, weights 13.6gr-13.7gr. 730-734fps. Upper target of target with 2 targets

Crosman Premier 14.3gr Domed

10 samples. 0 damaged, all weighed 14.4gr, 700-711fps. Center target (#1-4) and lower target of target with 2 targets. 

Crosman Premier 14.3gr Hollow Points

10 samples, 0 damaged, weights 14.4gr- 14.7gr (9-14.4gr, 1-14.7gr), 701-711fps, center target (#5-8)

 

[bubblerboy64]

Damage is one thing but the difference in weight seems extreme. I don’t think we can draw any conclusions from such a limited sampling but needless to say something seems “off” 

 

[rsfrid]

I just weighed an entire can of JSB Monster 25.39gr and found less than 10% at the stated weight. They ran from barely over 25.0 gr up to over 25.8 gr with most in the 25.5 to 25.7 gr range. Pretty poor if you ask me. Guess they're slinging them out the door faster than they can weight check.

 

[egd]

I've wondered why pellet mfgrs list their pellets in such detail-11.42,25.39,10.34, etc. It seems kind of silly to me. Something so small mass manufactured for the price they are can't be that precise over the thousands produced. I don't see why they don't just say 11 gr, 25gr, etc.

If 25.4 is the target though, it seems to me that a variance of +/- .3 is pretty good. 

 

[Guest]

As pellet dies age they wear out. There are multiple dies used. The first ones you bought are likely a different lot than the ones you have now.

Your ES seem to be pretty good. Far better than most if not all .22 rimfire. As for accuracy you've entered the sorting and testing faze. Once you've found a lot that shoots well try and buy as many of that lot as possible. Or find a gun/barrel that shoots most rounds well.

 

[k-harr26]

Thanks for the info and opinions. This post is to see if anyone else has had the same issues or is this normal for this industry. At first we purchase several different brands, weights and styles of pellets. Did a lot of target shooting to find the pellets the guns like/ dis-like then purchase several tins. Now that we are running low on pellets and I re-stocked on what I assumed would be an "exact" replacement, I'm not seeing it. I tested several of the JSB Exact series pellets from our testing phase and found the weight variances mostly .1gr. It appears that JSB QC maybe an issue. I have contacted the vendor I purchased these from to see what they recommend. See I also shoot ELD and do all my own re-loading so I'm very familiar with projectile-load-primer variations to see what a particular gun likes. I wonder if should start the process back over of finding a new " lot" of pellets?

 

[bubblerboy64]

How do you go about buying ( or specifying a lot) Seems like you would have to have a “in” with some one. Or buy an extremely large order at one time. I also wonder how many tins are in a lot. My guns especially my 22rf always like the most expensive ammo best. RWS 50 eley tenex. But who can afford that stuff now? If you could get them. I have enough ammo for my life time. So it doesn’t matter to much to me but I’ve heard people talk about buying in one lot just never knew anyone who did it or anyone that was that good of a shot that it was of any practical value 

 

[k-harr26]

bubblerboy64 I recently purchased 10 500 rnd tins for one of the main online stores and I got what they sent me.. (no names as its not their fault and they are replacing the 2 damaged tins). There is nothing on the tin as to indicate a production date or "lot" #. I was wondering if others have run into a change in QC from JSB. Up until I have liked their products. I don't want to re-order and have the same problem. I'm wondering if they are rushing production to fill back orders which may be hurting QC or I got a bad run etc. 

 

[Scotty1]

My most recent order of JSB 18.13 are a bit different than my order before that, cup is shallower, and the skirt is a bit thicker. I don’t feel like they group as well, but my wind here is always different, and I can’t be positive. There are fewer damaged pellets in the new tins, perhaps that explains the change….

 

[BeMeUp]

I remember reading a post were someone deliberately deformed the skirt on several pellets and the fired fine out of his gun,the blast of air against the soft lead reshaped it,I’m gonna shoot a bunch of deforms to see if true

 

[Reidy]

I know that springers reform the skirts of pellets because of the severe blast of air that's caused by the piston causes them to balloon outwards but I thought the general consensus was that the air blast from a PCP was smooth enough that it mostly didn't reform damaged skirts?