Author Topic: Another cheap pcp  (Read 579 times)

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Offline Baggawind

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Re: Another cheap pcp
« Reply #10 on: February 11, 2017, 02:15:51 PM »
They never found anything at the hospital. Phew!! As for the cheapo, its not very accurate. I,ve re-crowned the barrel but still no joy. Bisley Magnums seem to be the best of the bunch but still not that good. Perhaps it will improve with a bit more leading up. The power has also dropped to around 10.5fpe. But then, regs do take time to settle. I figure I can get just over 100 shots per fill. Now i,m starting on the next one.  :)

Online Gambo

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Re: Another cheap pcp
« Reply #11 on: February 11, 2017, 05:13:51 PM »
Good news about the hospital. ;)

Maybe it has the normal SMK banana barrel......I've seen plenty where the bore is not straight in relation to the tube's exterior. :-\

Offline Baggawind

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Re: Another cheap pcp
« Reply #12 on: February 11, 2017, 08:40:08 PM »
When it came to threading the barrel for a silencer the bore was well eccentric. The frustrating thing is, it will shoot three shots in a cloverleaf then chuck a couple low. And some pellets, especially Air Arms wont, group at all, which is a surprise. It is a .177 so it could be that they can,t quite get them machined accurately. Having said that, my SMK208 is very accurate. I,ll try changing silencers, sometimes that makes a difference. These slug guns can drive you potty, like the bloody BSA Hornet I repaired last week. Talk about a badly designed and made rifle. :o

Online Gambo

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Re: Another cheap pcp
« Reply #13 on: February 11, 2017, 09:28:53 PM »
the bore was well eccentric.

I had three exchanged before I found a straight one.

It's just luck of the draw whether you get a good one or not.

Offline Baggawind

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Re: Another cheap pcp
« Reply #14 on: February 12, 2017, 11:03:18 AM »
Well, I thought i,d cracked it. Wrong ! I had another look at the muzzle. I tried the old trick of pushing a pellet in from the muzzle end then slowly pulling it out. I found that Sniper mediums were perfect for this as they have a distinct edge at the back of the head. And, sure enough, it was catching on a burr. So some VERY careful work with a needle file and a jag wound with wire wool removed the burr. Back to testing. Using my favourite Sniper mediums it started putting pellet on pellet. Great. The strange thing is, using different pellets produced groups but, at only 21 yards, they went 15mm right or left depending on the pellet being used. Sniper Lights grouped but 15mm to the right. BisMags grouped quite well but to the left  :o. Then I went back to mediums only to find that after putting in tiny groups, it suddenly started shooting to the left. Guess i,ll have to try a different method of crowning , perhaps leaving out the countersink and simply having a sharp edge square to the bore. Any ideas folks?

Online airgunnut

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Re: Another cheap pcp
« Reply #15 on: February 12, 2017, 12:13:12 PM »
Well, I thought i,d cracked it. Wrong ! I had another look at the muzzle. I tried the old trick of pushing a pellet in from the muzzle end then slowly pulling it out. I found that Sniper mediums were perfect for this as they have a distinct edge at the back of the head. And, sure enough, it was catching on a burr. So some VERY careful work with a needle file and a jag wound with wire wool removed the burr. Back to testing. Using my favourite Sniper mediums it started putting pellet on pellet. Great. The strange thing is, using different pellets produced groups but, at only 21 yards, they went 15mm right or left depending on the pellet being used. Sniper Lights grouped but 15mm to the right. BisMags grouped quite well but to the left  :o. Then I went back to mediums only to find that after putting in tiny groups, it suddenly started shooting to the left. Guess i,ll have to try a different method of crowning , perhaps leaving out the countersink and simply having a sharp edge square to the bore. Any ideas folks?
Some one I know uses a round ball grind stone in a dremal type tool, no matter what angle the dremal is to the barrel the ball grind stone is at correct angle and he just touched the muzzle with the stone, no need to countersink it by 2inch like some recrowning does
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Online Gambo

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Re: Another cheap pcp
« Reply #16 on: February 12, 2017, 12:39:13 PM »
I've seen that technique used before, and also a round headed brass screw used for the same effect.

I think MidwayUSA do a YouTube vid about it. ;)

Offline Baggawind

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Re: Another cheap pcp
« Reply #17 on: February 12, 2017, 05:58:15 PM »
That,s what i,ve just done. I used a ball bearing and fine grinding paste after firstly machining the barrel face square with the bore. I haven,t tested it yet though. Perhaps tomorrow morning , before I go to my brother,s funeral ( another one ). I,ve also started work on the next one. 

Offline Baggawind

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Re: Another cheap pcp
« Reply #18 on: March 08, 2017, 06:51:34 PM »
Well, after much faffing about I think i,ve sorted it. It seems the breech was the maim problem. I noticed it was difficult to seat a pellet so I drilled the bore slightly deeper and used a tapered reamer to ease the lead in. It seems to have done the trick. Crazy thing is, I bought some BSA Red Star pellets in the quest to find some cheaper but accurate pellets. And I have to say, they are the crappiest pellets i,ve ever seen. Odd shapes, lots of flashing on the skirts, different depths inside. Really awful. But, I used them this afternoon and , guess what , they printed one hole groups at 21 yards  :o . Doesn,t make sense . Bloody slug guns  ::)

Offline shakeysimon

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Re: Another cheap pcp
« Reply #19 on: March 08, 2017, 07:57:25 PM »
I do remember someone else saying about 2/3rds of inaccurate rifles are caused by the breech,pellet probe or poor magazines,kinda makes sense,hope you get it sorted
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