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Update Bowkett .25 cal BSA Hornet shot string etc. Long ...

Posted: Wed Jul 08, 2009 11:27 am
by Yrrah
Ogre6br asked for an update.
Here is a shot string with .25 Kodiak Match pellets nominal 30+ gr.

Image

Note that the reservoir on this rifle is only about 165 cc not 400 or 500 cc as in some rifles.

27 shots; Extreme spread 14 fps with 25 shots in an ES of 10 fps; 49 fpe KE; 848 fps MV with 30.7 gr Kodiak .25 cal pellets.

Readings at 2.5 ft from muzzle to mid point between sensors. (Note: Actual muzzle velocity is about 2.5 to 3 fps faster):

845
846
847
849
844
840
843
845
844
845
843
839
846
845
841
843
847
845
846
853
847
848
850
849
845
847
845
Reservoir approx 165 cc ( my measurement ).
Pellet average 30.7 gr Beeman Kodiak Match .25 cal.
Average 845.4 fps at 2.5 ft ( = MV 848 fps; ME = 49 fpe)
H 853 fps
L 839 fps
SD 2.95 fps
ES 14 fps
Fill pressure 250 bar; end 155 bar;
Efficiency 11.8 bar-cc/fpe.

Since posting these targets (below) I have not had the opportunity to shoot at longer range and it will be a couple of weeks before I do: The 75 yd target was the only one shot. The wind was a factor in the lateral spread of some groups. I think the best may be yet to come.

Image

Furthermore I weighed a random sample of 20 Beeman Kodiak .25 cal pellets and got a weight variation of 1.3 gr between heaviest and lightest. The above shot string may have been even tighter with weight matched pellets. I have now received a small sample of old H&N Baracudas from John Bowkett. Their weight variation for 20 random pellets from the tin is only 0.40 gr and these are not marked as "Match". I am looking forward to testing them but unfortunately the batch is long gone :( .

The computed energy at 75 yards is 31+ fpe and the estimated penetration depth in animal tissue at that range is 8.0 inches or 20 cm ! Watchoutfoxes.

I hope this is of some interest ...... Kind regards, Yrrah.

Re: Update Bowkett .25 cal BSA Hornet shot string etc. Long ...

Posted: Wed Jul 08, 2009 1:23 pm
by daisy
Hi Harry,

How does that compare to the 22 cal string ?
It looks good for silhouette. Wouldn't Dave True like to watch his chickens fly with the 25 cal. He likes to have a go at me for sending them out to the turkeys with the Excalibre. :wink:

I sometimes think that a JB in 177 would make a great silhouette gun.

Daisy

Re: Update Bowkett .25 cal BSA Hornet shot string etc. Long ...

Posted: Wed Jul 08, 2009 1:57 pm
by ogre6br
At the moment im having trouble doing groups tripple that size at 30 yards-
not 50
and let alone 75 yards

I dont know whether it's me going sour or the barrel needed a cleaning pellet down it or ???

but the last time i was out the wind was up a bit and the target looked like it was sneezed on- not a series of groups at all

and that was at 40 yards

the FTS and Kodiaks were still going through the 12mm melamine shelving that was the target frame backing like it wasn't there so thats a good thing

the penetration is there even if my accuracy is not

27 shots out of such a small air cyclinder- the vavling on that regulator must be top notch and mega efficient

P

Re: Update Bowkett .25 cal BSA Hornet shot string etc. Long ...

Posted: Wed Jul 08, 2009 5:38 pm
by Yrrah
Daisy, here is a shot string from the same rifle when it had the .22 barrel installed. In this case the pellets are the Baracuda .22 pellet of 21+ gr.

Image

You will see there are about 27 shots ( #4 to #30 inclusive) there with an extreme spread of 10 fps and the whole 32 shots would be in the ES of 14 fps. .. Note that although the string was chronographed at 42 ft from the muzzle the velocity iindicated has been graphed at muzzle velocity. It was running quite hot then. That computes as 41 fpe as against the 49 fpe now with the .25 cal Kodiak 31 gr pellets.
In .22 mode it did go to 45 fpe with 28 gr Eunjins. The best they did was the same velocity as the 31 gr Kodiak/ Baracudas are doing with no change to the tune of the rifle and a 4 fpe increase in KE.

For such a small air reservoir this rifle is very efficient.
We will have to have a 100 metre session on the rimfire rams again some time :lol:

Hope all is well with Lois and yourself. I will get back down there some day ( with some more flathead fillets perhaps :D )
... Kind regards, Harry.

Re: Update Bowkett .25 cal BSA Hornet shot string etc. Long ...

Posted: Wed Jul 08, 2009 6:04 pm
by Yrrah
ogre6br wrote:At the moment im having trouble doing groups tripple that size at 30 yards-
not 50
and let alone 75 yards

I don't know whether it's me going sour or the barrel needed a cleaning pellet down it or ???

But the last time i was out the wind was up a bit and the target looked like it was sneezed on- not a series of groups at all

and that was at 40 yards

the FTS and Kodiaks were still going through the 12mm melamine shelving that was the target frame backing like it wasn't there so thats a good thing

the penetration is there even if my accuracy is not

27 shots out of such a small air cyclinder- the vavling on that regulator must be top notch and mega efficient

P
I'd give the barrel a thorough clean if it was mine P. More and more, regardless of what others may write, I feel barrels need regular cleaning. A lot of the "basement 15 yard" US shooters would not find much difference. But when the range is stretched out "beyond" I think it shows. Lampies Lamprecht in South Africa thinks the same and he, too, has shot many and wonderful 100 yard sub inch groups with more different rifles and calibres than I have ( .177, .20 and .22 ).

Yes, this is a very efficient rifle.
I'm now sizing the Kodiaks by forcing them into half of a Parker ballpoint pen, then pushing them back to a flush skirt and gently wiping off the flashing flush. ... When Lewis gets back I'm hoping he may be able to dig me up a Beeman sizing die in the size I think might work.

How many shots do you get inside a, say, 15 to 20 fps spread and what is the size ( 400 cc? ) of your reservoir? Not that it matters as each shot is a bunny, right? :D and you can only eat so many! ............ Kind regards, Harry.