Harmonics damping of a barrel .. 50 metre Target ..luck?

[Yrrah]

Yesterday I attended a club rimfire 50 metre shoot and took my first BSA Hornet air rifle which the mob accept and quite enjoy seeing shot.

I did a little, easily reversed, mod to my free floated BSA Hornet barrel. I inserted a strip of Blue Tac with its protective strips between the barrel and the air reservoir near the muzzle.
Following a brief sighting in for my detail, I shot this one group ( signed by the Range Officer ) .. A wind change caught me off guard for shot # 4 of the five shot group. It is not a miscreant flier. I watched it curve and saw the flags flying left ... Those four measure just 0.15 inch ctc 3.81 mm at 50 metres/ 55 yards.. The whole group is 0.50"

http://img.photobucket.com/albums/v392/ ... sts058.jpg" onclick="window.open(this.href);return false;

Here is the barrel with the Blue Tac inserted and lightly pressing the barrel and reservoir. I grooved the BT both sides and slid it in from the front.

http://img.photobucket.com/albums/v392/ ... 056jpg.jpg" onclick="window.open(this.href);return false;

That was the only group shot but obviously the BT didn't make anything change for the worse....... The pellets were the new 18.1 gr JSB Exact Jumbo Heavies which I tested at the beginning of the year and which came onto the market a month or so back. Lewis got a consignment from the first batch. The MV today was 840 fps 28.4 fpe shot from the first BSA .22 Hornet not JB OZ 1..........

Harmonics damping? Could be my rifles still have something to give. We'll see in time.
... Kind regards, Yrrah.

[fritz]

Wow Harry, nice shootin'!

[RayG]

That was an interesting experiment Harry. It proves again that curiosity is never ending in pushing the envelope of airgun performance.

Incidentally, have you had similar weights per tin in the new Jumbo Heavy pellets compared to the tin I weighed?

[Approximate estimate of 50% were right on 18.1 Grn; 49% were 18.2 Grn,18.4 Grn,18.5 Grn and 1% were 17.7-17.9 Grn.( This would of course vary from tin to tin).]

I was a little surprised but apart from the few pellets that were below 18 Grns
I reckon the rest of the tin that weighed from 18.2 to 18.5grains will not make a jot of difference
in hunting performance with my guns.
On the other hand as you have always said, weigh and batch your pellets to suit your purpose, whether it be target shooting or hunting.

I will be quite happy when I get my TTR1 back from Lewis and finally put it through its paces with the Jumbos. It shoots very well with the Exacts so my expectations are High.
Happy New Year!
Ray.

[ogre6br]

interesting
might give that a burl with the Rapid .25

with the 500CC cyc on the barrel and cyc come quite close togethere and sometime touch depending on how it's held
or if ther big torch is mounted up the front

later
p

[RayG]

Hey P,
Also as a matter of curiosity, what sort of groups do you get with your Rapid .25 at 50 metres,I wonder what the blue tac will do for it?
So far I have not had a close look at the .25 cal,but it looks like there could be some interest in it for me.
The only gun I have used in .25 was a Kodiak (Webley) a mate of mine traded a shotgun for it a while back. That is one big Thumper of a springer,it can hit hard.
Happy New year.
Ray.

Aw Phooey! missed agin,I'll git ya next year Terkwy!

[ogre6br]

I'm on the lappy down the BIL holiday house ATM. The pics are on the desktop at home.

Have a search for my user name and under the airgun boards only

You should be able find my pic of 24 shots at 20m in the underground range

the other thing is you cannot base your decisions on my shooting ability- I have the shakes from the chemo treatment
I cannot shoot for shit these days

I let my cousin use the .25 cal and he put at magazine (12) that was covered by a 10c piece- there were some holes that weren't conpletely covered but all holes had some part of the 10C covering them at 25M in the chook sheds at his place.

later
p

[Yrrah]

That was an interesting experiment Harry. It proves again that curiosity is never ending in pushing the envelope of airgun performance.

Incidentally, have you had similar weights per tin in the new Jumbo Heavy pellets compared to the tin I weighed?
Happy New Year!
Ray.

Ray, I have just weighed 50 of them on my RCBS powder scales.
I get: 23/ 18.1; + 21 / 18.0 = 88%
4 / 17.9 = 8 %
1 / 17.8
1 / 18.2

That looks like excellent consistency with 96 % within +/- 0.1 of 18.0 gr. ( Note, I have not used calibration masses so it could be that they are all a fraction heavier ).

You couldn't have had a bit of air movement where you were weighing? It takes very little to make things vary more than they really do.

Kind regards, Harry.

[RayG]

Harry,
Those weight figures do look somewhat better than the pellets in my trial tin.
The conditions in my den were quite steady and the electronic scale was level and calibrated to makers instructions. Just to eliminate any possible glitch with my electronic scales I will weigh the pellets again with my RCBS Beam scales.
Either way the total weight differential in my pellet batches is under half a grain per pellet on the average, which to me is quite acceptable in well made pellets anyway.
It all helps to keep the grey matter sparking as well.
Cheers Ray.

[Yrrah]

Harry,
Those weight figures do look somewhat better than the pellets in my trial tin.

Cheers Ray.

Ray, if that was a tin of the original pre-production pellets from back early in the year, that could be the answer. They shot very well ( sub 100 yd moa, 0.375 in at 65 yd ) but they were not quite the finished product. I gave some feedback on a tooling adjustment issue to Josef to which he responded. The production run are pretty much perfect. I have as yet to even identify a "fingerprint" that I can use to index them into the chamber....... Kind regards, Harry.

[RayG]

Harry, The pellets I weighed are from the factory order from Lewis. So I assume (sometimes a mistake, Mum said never assume!) that the pellets should be relatively the same weights.
On examination as you say the pellets are very well formed with no odd bumps or sharp edges,
the guys at JSB do it well.
Basically the weights are consistent with my original check and are very close to your numbers anyway. After weighing 3 batches of 10 pellets they average out at 18.12 Grns.
Still again the variance in pellet weights over all in the tin is under half a grain,which is not a lot in my book.
Here are the figures from a reweigh on my beam scale of 50 of the pellets from the tin under scrutiny.

27/18.1, + 13/18.2 = 80%
6/18.4 = 12%
3/17.9 = 6%
1/18.5

Please don,t think that I am tying to be smart about the whole exercise on the pellets, Its just that my curiosity about the weight consistency of them and my interest and fiddling evolved from that. The info from this look at the pellets will obviously be of benefit to me in the field.

Happy New Year!

Ray.

[RayG]

[Quote]
You should be able find my pic of 24 shots at 20m in the underground range
the other thing is you cannot base your decisions on my shooting ability- I have the shakes from the chemo treatment
I cannot shoot for shit these days

I let my cousin use the .25 cal and he put at magazine (12) that was covered by a 10c piece- there were some holes that weren't conpletely covered but all holes had some part of the 10C covering them at 25M in the chook sheds at his place.

Hey P,
Stuff the shakes mate! The main thing is you can get out there and shoot it!
The 20 Metre group looks OK P, and if your Cuz can shoot that size group at 25M
there aint anything wrong with the .25.
The power setting of 45 Ftp would no doubt give the Rapid some good fox bustin' capabilities at the right ranges,that is why I have got a bit interested in .25 a bigger/heavier pellet and a bit more grunt can go a long way.
I hope you have a better year in '09 mate,
cheers Ray.

Hey Wabbit wait up!

[ogre6br]

Ray if you have charigun2

put the figures in
.25 cal Kodiak ( or K match) at 48 FPE (840 FPS) zero at 45 yards
gives you about 2 and a bit inches low at 60 yards with 32 FPE energy

a high % of airguns nver put out 32 FPE at the muzzle- let alone at 60 yards

now you know why I like it so much
BTW I get 5 magazines worth before having to re-charge using the 500CC bottle filled to 220 BAR and refilled after the 5 magazines worth.

But you also now know why even with Crow magnums I'm going through the "rats with wings" and the roof tin at 10 yards into the roof of the mates barn

P

[Yrrah]

Ray if you have charigun2

put the figures in
.25 cal Kodiak ( or K match) at 48 FPE (840 FPS) zero at 45 yards
gives you about 2 and a bit inches low at 60 yards with 32 FPE energy

a high % of airguns nver put out 32 FPE at the muzzle- let alone at 60 yards

now you know why I like it so much
BTW I get 5 magazines worth before having to re-charge using the 500CC bottle filled to 220 BAR and refilled after the 5 magazines worth.

But you also now know why even with Crow magnums I'm going through the "rats with wings" and the roof tin at 10 yards into the roof of the mates barn

P

.22 Eunjin 28.5 gr at 60 yd with 31 fpe punch remaining; I'm sure you will remember this:

http://img.photobucket.com/albums/v392/ ... it60yd.jpg" onclick="window.open(this.href);return false;

I'm getting John Bowkett to send me a spare BSA .25 barrel and receiver and bolt probe to bolt onto JB OZ 1 for a while in place of the .22 barrel ......... ready to test some JSB .25s sometime this year for you .. ... Have patience ... Kind regards, Harry.

[RayG]

[ Quote Ogre] a high % of airguns never put out 32 FPE at the muzzle- let alone at 60 yards.

Yes mate,
That is exactly why I am getting interested in the .25.
It would fill another slot in my hunting airgun lineup,a bit more grunt at the target end would be a good thing on some of the small holdings I shoot on.(where I cannot use Rimfire or shotty).
Although in the main the .20 and the .22 cal guns really do their bit for me,one more powerful "Thumper" will add a bit more scope to my airgun shooting.

It will be a treat to see what Harry can do when he gets the .25 barrel for his OZ 1 "Beeza".
We are very lucky to have a guy with his expertise in our AG scene here. I have learnt heaps in recent times from his research.

Cheers Ray.