Put a .25 cal barrel on a late model R1/HW80

[DanD]

I have a later model R1 with an ARH Ultramag spring in it.
It was making 20 harsh ft-lbs with a 16" .22 barrel - FTT 14.66 gr @ 778 fps.
I just put a 16" .25 cal barrel on it and it shoots much more pleasantly at 17.5 ft-lbs with FTT 20.06 gr @627 fps.
For plinking I'll take the energy loss and pleasant shot cycle every time, but if I were hunting with it, I'd go with the faster, more efficient .22.
Just thought I'd share my findings.
Have fun!

[KWK]

My Tomahawk is lighter than your HW and whips those FTT's out at 725 fps. It's no pussycat but great fun to shoot. I really enjoy shooting it off hand. Soda cans at 55 yards a few weeks ago.Easy. And little seed balls from a sycamore tree. .25 delivers some impact. Been shooting JSB Kings out of it. Original Spring. Tomahawks don't twang but Webleys can be jumpy. Doesn't bother me at all. I'd like to whack a squirrel with it some time or a starling just to see what it does to it. .25 Tommy kicks butt AND  it's pretty. Will not part with this gun. My all time favorite plinker. Probably.....
5 FTT's at 25y

[Toxylon]

Good to hear, Dan!

Your .25 cal numbers jibe with other user reports on the HW80, in stock form (I know you used a Maccari spring). Many people have tuned their .25 cal 80's into the 30J (22 fpe) range, with still very usable cycles. That works out to around 700+ fps with the FTT's.

[Bayman]

Good information Dan. Thank you. I thought I've worked on R1s in every caliber but I was wrong. I forgot about 25. I'm surprised that the energy went down. It usually goes up between caliber increases with the other three calibers. All that matters is you're enjoying the gun more.
Be well
Ron

[KWK]

Yeah, that's what I thought, too. And possibly shoot smoother as well.

[DanD]

I remember reading somewhere that .22 is usually more efficient than .25 for springers, so I expected a slight loss in energy but I didn't think I'd lose so much considering how oversprung the gun felt in .22.
I just chronied .25 cal Predator GTO 16.56 grain alloy pellets at 745 fps for 20.3 ft-lb. I wish I tested alloy pellets in the .22 barrel before I swapped it; I think they would have been in the 21 to 22 ft-lb range.

[AjaxTL]

where did you find the .25 cal barrel?  I have been looking

[DanD]

where did you find the .25 cal barrel?  I have been looking

Had one on back-order through Pyramyd since Nov, then a few weeks ago they declared it discontinued and cancelled my order so I ordered this one from Chambers UK.

[Toxylon]

Just this week I was checking on replacement parts for my Mercury on the Chambers site, and when it came to replacement barrels the product descriptions had a statement: "VCR Bill - UK Customers Only". In the past there was no such limitations in place.

[AjaxTL]

where did you find the .25 cal barrel?  I have been looking

Had one on back-order through Pyramyd since Nov, then a few weeks ago they declared it discontinued and cancelled my order so I ordered this one from Chambers UK.

Thanks.  Did it come complete or just the barrel

[AjaxTL]

Just this week I was checking on replacement parts for my Mercury on the Chambers site, and when it came to replacement barrels the product descriptions had a statement: "VCR Bill - UK Customers Only". In the past there was no such limitations in place.

Yes VCR appears to apply to UK customers only.

[Bayman]

Unless it's changed two years ago I bought a 177 P1 barrel and a year ago a 20 cal R1 barrel from Chambers. Oddly they wouldn't sell me a HW95 wood stock because of some weapons shipping ban.

In the UK you can't buy a barrel without trading one in. I believe they have to be serialized to do so. Big pita for them.

[DanD]

.....  Did it come complete or just the barrel

The barrel comes with the breech seal and detente plunger and spring installed.  It does not include the cocking link and rivet.

[lillysdad621]

Dan the 16 in barrel on the R1 is the Karbine size one (R1 were available in carbine or rifle size), and your velocity loss comes from the barrel being a bit too short for the spring in the gun. I bet a little more barrel would have put you in the 19-20 fpe range without a problem. And as far as the available R1 barrels made, well, thru beeman we had the expected 4, but out there are 5 .30 cal barrels (i know where one went...) and 2 .32 caliber ones. The last one is the one i have never seen. The .25 in rifle size (19.25 in) was what also came in the RX1 and RX2, which were able to shoot at well over 24 fpe.

[UnderPressure]

I have a later model R1 with an ARH Ultramag spring in it.
It was making 20 harsh ft-lbs with a 16" .22 barrel - FTT 14.66 gr @ 778 fps.
I just put a 16" .25 cal barrel on it and it shoots much more pleasantly at 17.5 ft-lbs with FTT 20.06 gr @627 fps.
For plinking I'll take the energy loss and pleasant shot cycle every time, but if I were hunting with it, I'd go with the faster, more efficient .22.
Just thought I'd share my findings.
Have fun!

Very interesting findings considering the projectile sectional density of .25 cal ftt pellet @20.06 grains is only slightly higher than the 14.66 grain .22.

That means your pellet starting pressure wasn't much  different than the .22 but the air volume it displaced when moving down the barrel was.  (starting pressure for pellet movement is both a function of projectile sectional density and friction due to projectile bearing surface length.)

Obviously the cushion of air which normally causes piston bounce decreased in strength resulting in a less lively shot cycle.

P.S. Just for the sake of discussion any time caliber is doubled and projectile design is kept the same (i.e. all projectile dimensions scaled up proportionally to the caliber increase) bore diameter surface area of projectile increases by 4, bearing surface area of projectile increases by 4 ( 2 x due to increased circumference of circle and 2 x due to increased projectile bearing length. Therefore 2 x 2 gives you 4) and weight of projectile increases by 8 (projectile diameter surface area of 4 x  increase in projectile length of 2 gives an increase in 8 because 4 x 2=8) The case of comparing 14.66 grain .22 to 20.06 grain .25 is quite different though because a 20.06 grain .25 is not a scaled up 14.66 grain .22.  What we have here  is a projectile with a slightly higher starting pressure due to slightly higher sectional density but at the same time (I believe) benefitting from a lower ratio of  friction to pellet bore size surface area which at the same lowers starting pressure requirements. Of course pellet alloy hardness differences, rifling land/groove configuration differences and rifling twist differences ....among other things....would play a role in starting pressure as well.

[AjaxTL]

.....  Did it come complete or just the barrel

The barrel comes with the breech seal and detente plunger and spring installed.  It does not include the cocking link and rivet.

Thanks!

[DanD]

Thanks for your input, guys. It's an interesting discussion.

....
Obviously the cushion of air which normally causes piston bounce decreased in strength resulting in a less lively shot cycle.
...

Hi UP,
I surmised just the opposite. I thought the .22 shot cycle seemed really slammy with a sharp muzzle blast, but the .25 FTT at 17.5 fpe seems like it might be mellowed by more of an air cushion at the end of the stroke. The lighter .25 GTO pellets made more energy, but felt slammy again. This may be due to pellet fit for that particular barrel.

Dan the 16 in barrel on the R1 is the Karbine size one (R1 were available in carbine or rifle size), and your velocity loss comes from the barrel being a bit too short for the spring in the gun. I bet a little more barrel would have put you in the 19-20 fpe range without a problem. And as far as the available R1 barrels made, well, thru beeman we had the expected 4, but out there are 5 .30 cal barrels (i know where one went...) and 2 .32 caliber ones. The last one is the one i have never seen. The .25 in rifle size (19.25 in) was what also came in the RX1 and RX2, which were able to shoot at well over 24 fpe.

Hi LD,
I ran a full length .22 HW80 barrel and a 16" .22 HW80K barrel on this R1/ultramag action, and both barrels happened to make 20 fpe. But that is only two test points, so perhaps a larger sample would show power increasing with barrel length. Or maybe the R1/HW80 action doesn't gain as much power from longer barrels as other actions- I don't really know- just thinking of loud.
The new 16" .25 cal barrel is marked HW95.

[Crowman]

I have a 80k .25. About month ago I gave it a Vortek spring and piston seal. On the crony I was getting 585 fps. Haven’t shot it since that I remember. I’m wondering if my crony is out. Crow

[lillysdad621]

The new 16" .25 cal barrel is marked HW95.

I bet it does... its being a while since the R1 carbine was available, and then the HW95 was offered in .25.

[UnderPressure]

Thanks for your input, guys. It's an interesting discussion.

....
Obviously the cushion of air which normally causes piston bounce decreased in strength resulting in a less lively shot cycle.
...

Hi UP,
I surmised just the opposite. I thought the .22 shot cycle seemed really slammy with a sharp muzzle blast, but the .25 FTT at 17.5 fpe seems like it might be mellowed by more of an air cushion at the end of the stroke. The lighter .25 GTO pellets made more energy, but felt slammy again. This may be due to pellet fit for that particular barrel.

When using the .25 GTO you mentioned it feeling slammy, but did you also hear an increase in noise compared to the .25 FTT?

Both the .25 GTO and the .25 FTT  should have the same muzzle report due to the air pressure at the muzzle being the same because they both share the same barrel volume. However, if the .25 GTO is indeed causing piston slamming there should be an extra noise (from piston hitting metal around transfer port) associated with that? Did you notice that extra noise?