New barrel problem(Newbie)
Hi guys,i’m new to the forum but have been reading and learning for a few month now.So i would like to say a big thankyou to all of you for keeping me amused,educated and inspired.
To the matter at hand.I own a Gunpower Stealth with a 12″ LW .22 barrel 😀 and have been consistantly shooting H&N FTT 15.55 gr pellets @ 650fps over the chrony on a 2800psi fill.I ordered a brand new LW 18″ .22 yesterday,which arrived this morning(impressive).A quick clean of the new barrel rifling to get rid of excess production swarf and into the Stealth it went.
Expecting the fps to go up by 90fps i was shocked to find it had gone down to an average 580fps 😥
I have made no new adjustments to the top hat sine the swap,so i’m stumped as to the cause.
Maybe i’m missing something or the barrel needs a bedding in periond before velocity improvements are noticed.
Any ideas anybody?
My five wives.
All Replies
Yeah i know what you mean m8, geoff is a top bloke seriously, has done me good.
well fingers crossed you’ll get there sooner or later 😀
Hi Zashark,
Sorry,i didn’t see your post there.
Yeah i did get it from gunower and what a top guy Geoff is.I’ll try all other options first including running it in before i then hold my hands up and give Geoff a bell.Thanks for the advice,its an option i’d never even considered which is strange cos if it was a faulty tv,pair of socks or even a bottle of ketchup i’d be back to the store. 👿
Yo Pablo,
I’m on the Lancs Yorks border though with a bit of luck,not much longer.Im in the process of winding things up here prior to emmigrating to Africa with a couple of ex squaddie buddies of mine. 😉
I’ll be turning out the top hat tomorrow.I’ll be happy to just reach anywhere over the 700 mark to give me that flatter trajectory over 50-60 yards.
Mike
I have held an F.A.C since 1986.
Your correct in the fact that i don’t have the F.A.C model,however the valve has more than adequate airflow to achieve F.A.C velocities.20ftlbs was easily achievable with the 12″ barrel but i kept it turned low to save on air and shooting around farm buildings did not warrant it where ricochets where probable. 🙁
Brent
Hi
Did you buy the barrel from gunpower? if so could always give geoff a ring to see what he says, just a thought.
Since your in the UK, it is very possible that you don’t have a FAC Model.
If that is the case, you probably have a valve aperture even smaller than the micro meter valve. If this is the case, you are simply running out of air. Do you have a FAC certificate? If so, we can be a lot of help to you here. 😀 if not, I’m afraid there isn’t much we can do for you as to power increases. 😳
Mike
I have had the valve apart.Although it is structurally different from any valve i have seen before it has good airflow with two large slots on the valve side towards the rear.
Yo Wolfy, nice to see another Brit on the site 😀
I’m in Lincolnshire, how about you??
IMO i reckon you need to wind out the th a bit. Is the valve spring retainer bored out?
I pre-loaded the hammer spring a bit to increase fps to good effect, though i am a newbie to the Storm (Talon)
Sorry ‘Big Dawg’ if i’m posting above my station!! 😕
Have you ever had your valve apart? Does the spring retainer have a small air hole or a large one?
Larger = more airflow = more power
Thanks Spyder,I can only use one at a time and having more of em means i loose valuable hunting time figuring out which one to use.
Hi Langnasen,
Your diagnosis sounds completely logical although i had it worked out the other way.The longer the barrel the more chance the projectile has to build up speed in front of a given pressure before that pressure is released on the exit from the barrel of the projectile hence the difference between a 6″ peashooter to a 6ft blowpipe,both using the same lungpower
Just a thought,though i must admit that friction must play a huge part regarding velcoity.
Brent
I’d think that if you were blowing excess air on a shorter barrel you’d see an FPS increase on a longer barrel as that excess air was put to use. If you were on the margin already (not blowing much or any excess air on a shorter barrel) you’d see an FPS decrease on a longer barrel.
I know a longer barrel makes better use of a given amount of air, but there has to be a point where the extra friction can outweigh it if the amount is not sufficient.
Off Topic comment,
Sure do like those Break Barrel models.
Never can have too many 😀
Hi Wok,
ID of valve stem is 3mm,a standard stealth valve with no internel restrictions given that its an English valve.Maybe it just needs a few hundred rounds of lead through it to blow out the barrel cobwebs.What do you think?
Brent
Are you using the micrometer tank? What is the I.D. of your valve stem?
Thanks guys for the possible reasons.I’ll go through each of those tomorrow.
Just checked the tophat gap,its at .075.Tried it without shroud this afternoon with the same low fps results.
Brent
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Thanks for all your help guys.I did all what was suggested and its done the trick as its now throwing out 15.55gr over the 700 mark.
I changed all the breach seals,polished the barrel breach and give quarter of a turn out on the top hat.
Brent