Diana mod 35 .22 Not Grouping

[snIPer]

Hi All,
I have a Diana Mod 35 .22

This has previously been tested for around 50 yards and found accurate.

I recently changed the spring to Gsmith and since then havent been able to group at all(tested at 10 - 12 yards) shots fly all around.
This is what i have done so far.

1. Fired approx 150 pellets so far to try to break in the washer n spring.
2. Tried diff types of pellets - Round Head (master shot 3 diff batches, Gsmith) , Pointed(master shot and one other brand), Double Head(master shot)
3. Stock screws are tight enough
4. Have used a rest (high stool)
6. Barrel cleaned when the washer and spring were changed.
7. No bend in the barrel
8. .... anything else i should be doing???

This is what i intend to do next.

1. Cut off one coil at a time and recheck.
2. Change washer if the above fails. * limited to a certain no of coils of course
3. Want to try longer ranges but my simple theory is that if it doesnt group at 12 yards it will surely not group at longer ranges.
Does anyone have any other suggestions???

[Mack The Knife]

Clean the bore. Put 25 shots through it and then check for grouping using the same pellets that gave you good groups earlier.

If this does not work, try another pellet but before you do, clean the bore again, put 25 shots through it and then try for groups.

Check the muzzle for a burr.

Recheck tightness of stock screws at frequent intervals.

Do not use a hard rest with a spring piston airgun. Keep a thick cushion or pillow on top of the stool but only rest your leading arm on it. Do not let the rifle touch the stool or cushion. Whilst this will help with grouping, expect the point of impact to change when shooting freehand.

Be very consistent with your shooting and don't shoot if tired.

Other than the grouping, in what way does the rifle seem different after the spring change?

P.S.: If you cut the spring make sure you grind the end flat and temper the end.

P.P.S.: Is the rifle dieseling heavily?

[snIPer]

Will try that - Thanks.
Other than the grouping there seems to be no difference at all in the rifle. The twang when firing is due to the new spring i guess.

How do i temper the end after grinding?

A bit of dieseling is there but it isnt heavy at all - I have a feeling that the local washer isnt able to support the spring - do you thing putting in a new washer will help (maybe cherokee or something branded)

[Mack The Knife]

The twang is due to the rear spring guide being a loose fit. Or in your case the ID of the spring being a bit more.

You can address this by putting more grease on the guide but your velocity will drop if you overdo it.

The correct thing to do is to get a spring with the right ID so that it is a snug fit on the guide or fabricate a rear spring guide for your spring.

[snIPer]

What do you mean by ID?
Any ideas on the fabrication of the rear spring guide.

[hellfire_m16]

Hi Sniper,

Gsmith recomends using their washer with the spring.

Best
-Vinayaka

[snIPer]

Hi Vinayaka,
Yes i did think that might be so. Cant find one in Bangalore so will try n get it from pune.
Thanks

[Mack The Knife]

What do you mean by ID?
Any ideas on the fabrication of the rear spring guide.

ID means Internal Diameter.

Take the rear spring guide and spring to a machinist and have him make a similar one, except that the guide (tube) will need to have a slightly larger diameter so that it is a snug fit on the spring.

[snIPer]

Ah Will do - Thanks Rusty