Consistency of springer muzzle velocities

[Malcytul]

Hi Antoni,
The inside of your gun should look clean but not dry, the piston & spring should have a light smear of grease & the piston head a thin smear of silicon oil.
I hold my combro on with elastic bands.
Your velocity will depend on which calibre you're using.
.22 weighing about 14.3 grains will be around 600ft/sec & .177 weighing about 8.5 grains will be around 775ft/sec.
Hope this helps.

[Antoni]

Hi Antoni,
The inside of your gun should look clean but not dry, the piston & spring should have a light smear of grease & the piston head a thin smear of silicon oil.
I hold my combro on with elastic bands.
Your velocity will depend on which calibre you're using.
.22 weighing about 14.3 grains will be around 600ft/sec & .177 weighing about 8.5 grains will be around 775ft/sec.
Hope this helps.

Thanks both.


Didin't know how to describe dry. Not Drizabone, no. But not wet and oily either. It looked sensible and I didn't add anything.

I'm not getting anything like 2.4 sd with my 177, hence the question. Iwas curious as to what folks thought normal for a springer, and I have a start, thanks.

[18 Wheeler]

If your HW80 is new then it will take 1000+ shots to stop dieselling and settle down. I'd consider a strip and relube.

If it's second hand then again you don't know it's history so a stripdown would allow you to check it over and lubing it should give good consitency assuming the basics are sound (Spring, piston seal, breach seal and no damage).

My 97 is tuned which clearly helps, but I recently bought a HW30 second hand and over the chrono with JSB RS (Falcon Acc Plus) the chrono readings gave a 3fps spread (6 readings were 676fps), that could be a freak data set with all the variables working for me.

It was only a 12 shot string because by then I had got all I needed to know. Legal, yes. Consistent, yes.

I would expect most springers to give 15fps spread or less with a pellet it likes, and the SD will probably be sub 5. Don't get too hung up on this though, what's the accuracy like?

[jay.t]

Thanks both.


Didin't know how to describe dry. Not Drizabone, no. But not wet and oily either. It looked sensible and I didn't add anything.

I'm not getting anything like 2.4 sd with my 177, hence the question. Iwas curious as to what folks thought normal for a springer, and I have a start, thanks.

You've not told us what readings you are getting, single figure spreads are great but even 20+ spreads may not show up when shooting on paper

[FPoole]

I like my TX's to run around 10 fps total spread in 10 unweighed shots. They don't always do this, but usually are close. I have one that will shoot as close as 4 fps spread with a SD of 1, but again not always. I tried a HW97 recently intendidng to buy. I put it over the chrony with Crosman Premiers and found it had a 2 fps spread in 20 pellets. Simply amazing and I had to check the chrony several times to see if it was working with so many pellets running the same fps. The only problem was that with a 1,000 shot practice over a weeks time, the gun simply would not group better than 1" at 25 yards. Many groups were much worse and all pellet types I tried showed the same results. I didn't buy the gun.

[aimhigh]

' a thin smear of silicon oil.

I would never allow this within 6 feet of any airgun - unless of course you like metal to metal contact

Ref:- http://www.airgunbbs.com/showthread....L-DAMAGE-Part2

[sevorg]

I've just finished setting up my 77 tonight and ran a few pellets through the chrony, I'll e-mail the excel spreadsheet to you...

Sevorg

[angrybear]

Hi,
don't know if these figures will be any use but my last test on my springer (Hatsan .25) with 4 different pellets gave 10-11-16-18 fps deviation on 10 shot strings,
but there's 1 pellet it doesn't like that has previously given 136 fps deviation over 20 shots.
steve

[severnsider]

Used a Combro, but fixed it carefully with a little BluTak, and gripped the mout hard when test firning to minimise relative movement between the barrel and the Combro

Antoni - this has been done to death in other recent posts, but you might find that more meaningful readings are achieved if (a) you hold the Combro on with insulating tape and (b) hold the butt firmly (e.g. against a tree or very firmly into your shoulder) to ensure that recoil is controlled consistently. If you have the rifle held loosely, readings will be very variable. Works for me.

[adesaxo31]

Iv read that with the little sunshades on the sensors it decreases the accuracy but it doesnt say how much I read it in the manual of my combro version 4

[Antoni]

What's the accuracy like? Dunno, I reckon the gun's more accurate than I am - as yet.

Readings so far? Not so much 3fps spread, more like 3ftlbs spread...

I am getting just abt 1" groups at 25 yds.

I heard: "Never allow sillicone within 6 mles of a paint shop". Thanks for the warning re anti-lubrication properties thereof.

Pure gold Mr. HW77. Ta for the Excel template too.

Thanks for the Hatsan .25 numbers.

I knew the Combro concept has limitations with springers, and wanted to show I'd tried to address them. Thanks for the pointers.