Pellet batch/die variation = big change in groups

[danco1987]

Hi all,

I've never had this before but wondering if anyone else has.

I have a ratworks tuned BSA scorpion in .177 which shots 5p groups with jsb exact heavies 10.34gr at 35 yards and beyond, easy and was laser accurate. Had it serviced and when it came back, it just wouldn't group, scattering all over the place to £2 size groups with flyers. I bought a single shot adaptor and saw no improvement. It went back and no problems were found and Phil at ratworks checked it over, thought it might be the bolt but it was pushing pellets in perfect and he even shot a great group at 40yards, with my scope on it and sent over pictures. That group was with jsb heavies.

I collected the rifle in September and haven't had it out until yesterday. Yesterday evening, try as I might, I just could repeat my 5p groups again, off the bipod like I used to. Checked power and it's consistent too.

It therefore can only be the batch of jsbs. My hw100 likes them and I haven't noticed any difference between batches for its performance but I think I have with my BSA before, it can only really be that which has changed. I'm fairly sure I was using a new tin when it came back from the service.initally and I noticed this accuracy change.

Has anyone has accuracy decrease and grouping open up this much from a different batch of pellets? From tight 5ps to scattered results in no wind?

I have some new stock of JSB heavies and maybe some left in old tins which I will try again today. If no success , I'll have to get some sample packs and see what it likes again but hope to get it shooting back the way it was with the heavies.

[Archer50]

Hi all,

Has anyone has accuracy decrease and grouping open up this much from a different batch of pellets? From tight 5ps to scattered results in no wind?

Simple answer, yes!

I don't have any experience of Scorpions, but I have lots of experience with JSB pellets in HW's, Steyrs and Daystates and the difference in performance between batches of JSB pellets (or any other pellet, come to that) can be extreme. Before spending too much money on the hunt for the perfect pellet, I'd clean the barrel and shoot 50 or so pellets before checking again. Also, have you put a mod or air stripper on the gun since it was tuned? If so, that will probably be the culprit. And is everything tight that should be tight?

Good luck

Alan

[danco1987]

Thanks for the advice. Should have said the barrel was cleaned and has had a 100 or so through it since.

Good to know it might just be the batch as I have some old stock I found in the loft, which I will give a go

Cheers

[Shed tuner]

yup, it can happen.
a certain die JSB caused my TX to drop about 3/4 of a foot pound and be considerably less accurate. Fiene in other guns though - and the TX is not at all pellet fussy generally.

[TonyL]

Yep, agreed, it most certainly can happen. Although it hasn't happened to me personally I once witnessed this very phenomenon at a Boinger Bash with some 8.44 Exacts. Rifle and scope etc. checked, double and triple checked. As a "wild" guess I suggested the user try a different tin of the same pellet and accuracy was restored.

[James1966]

I wonder if it is different shape/size of pellet or difference in material slightly harder or softer?

[ChrisC]

Without a shadow of doubt, that's why my last pellet purchase was chosen from 12 batches sent directly from JSB to try. I bought 10k euros worth for the cluster of HFT shooters who trialled them.