AusVarmint

Hi All,

A while back I had a thread going with Harry and Lewis relating to the regulated pressure in a Hornet .177.

Harry posted:

Let us know how many shots you get when you fill to 232 bar and drop it to say 120 bar ( you still get some good shots after it drops off the regulator as it then works as a self regulated rifle for a few shots before it dumps the rest. Usually when it comes off the regulator the velocity goes up for a few shots and then heads down ) ..... Kind regards, Harry.

Well, I finally stopped having fun long enough to actually get around to counting the shots........

I got 85 accurate shots from a 230bar fill, then it petered out over the next 4 shots, dropping to 150mm from the aim point (@ 50m). Shot #90 dumped the rest of the pressure.

Rifle is a standard .177 hornet. Pellets were JSB exacts (heavy).

Now I realise that this data isn't a scratch on what Harry does for us, but just in case anyone else out there was wondering how many shots were in a charge for this rifle, now we know.

regards, curan.

curan wrote:Hi All,

A while back I had a thread going with Harry and Lewis relating to the regulated pressure in a Hornet .177.

Harry posted:

Let us know how many shots you get when you fill to 232 bar and drop it to say 120 bar ( you still get some good shots after it drops off the regulator as it then works as a self regulated rifle for a few shots before it dumps the rest. Usually when it comes off the regulator the velocity goes up for a few shots and then heads down ) ..... Kind regards, Harry.

Well, I finally stopped having fun long enough to actually get around to counting the shots........

I got 85 accurate shots from a 230bar fill, then it petered out over the next 4 shots, dropping to 150mm from the aim point (@ 50m). Shot #90 dumped the rest of the pressure.

Rifle is a standard .177 hornet. Pellets were JSB exacts (heavy).

Now I realise that this data isn't a scratch on what Harry does for us, but just in case anyone else out there was wondering how many shots were in a charge for this rifle, now we know.

regards, curan.

Hey Curan, that is pretty good for a rifle that only has an approx 120 cc reservoir! As best I could, I measured mine at 119 cc after removing the fill plug, but I will stand correction if someone has done something tricky like filling it with water I joke of course. ........ Thanks for that, Kind regards, Harry.

Yrrah wrote:

pretty good for a rifle that only has an approx 120 cc reservoir

Hi Harry,
I suppose .177 uses less volume per shot than .22.
Apart from that, I don't know why it would do so well. But I'm happy.

regards, curan.

Thats a lot of pigeons per fill

Filling it with water is the easiest way to measure the volume. However it should have been done for you, there should be a water content weight stamped on the neck, depending on the country of manufacture it will have a prefix like WC followed by the weight of the water the cylinder will hold. We use this info when hydrostatically testing (pressure testing) the cylinders. 1 Kilogram of water = 1 litre = 1000 cubic centimetres (CC)

Rabz

curan wrote:Yrrah wrote:

pretty good for a rifle that only has an approx 120 cc reservoir

Hi Harry,
I suppose .177 uses less volume per shot than .22.
Apart from that, I don't know why it would do so well. But I'm happy.

regards, curan.

Don't think that is quite true - you would think so but it's not...

This is from Theoben's Web Site from a Spec Sheet of one of there PCP's (http://www.theoben.co.uk/pages.php?pageid=7" onclick="window.open(this.href);return false;)
Calibres Power Shots
.177 12ft/lbs 200
.177 17ft/lbs 70
.177 20ft/lbs 50
.177 23ft/lbs 40

.20 12ft/lbs 270
.20 27ft/lbs 40

.22 12ft/lbs 300
.22 30ft/lbs 50

.25 33ft/lbs 70
.25 35ft/lbs 60
.25 40ft/lbs 33

(12ft/lbs is UK max Limit befer you have to get a FAC license)

You accually get more shots per fill for same canister in a bigger caliber.

Don't think that is quite true - you would think so but it's not...

Wow, Gigitt.

I don't for a second disbelieve what you're telling me, but I can't for the life of me understand why it would be so.

I'll have to dwell on this for a bit, and see if I can get my head around it.

Thanks for the thought.

regards, curan.

curan wrote:

Don't think that is quite true - you would think so but it's not...

Wow, Gigitt.

I don't for a second disbelieve what you're telling me, but I can't for the life of me understand why it would be so.

I'll have to dwell on this for a bit, and see if I can get my head around it.

Thanks for the thought.

regards, curan.

On reading about it can be a couple of things

the smaller diameter the tighter the pellet fit within the barrel rifling the more resistance to get the pellet out the more air pressure needed means more air used.

you can push air faster with a bigger diameter hole meaning less pressure and less air used.

something like that.