Canadian Airgun Forum

The #1 Community for Airguns in Canada!
It is currently Wed Nov 20, 2019 7:57 pm

All times are UTC - 5 hours


The Canadian Airgun Forums are a place for people to discuss and learn about airguns and the airgunning sport in Canada. There are lots of discussions about airguns, airgun accessories, reviews, modification and repair information, airgun events, field target and free classifieds!

 

You need to register before you can post: click the register link to proceed. Before you register, please read the forum rules. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own pictures, and access many other special features. Registration is fast, simple, and absolutely free! To start viewing messages, select the forum that you want to visit from the selection below.








Post new topic Reply to topic  [ 2 posts ] 
Author Message
PostPosted: Tue Dec 22, 2015 12:52 pm 
Offline

Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
From so many disasters and setbacks to a better than expected outcome - I couldn't be happier. After the valve body broke in two it was Dan 'sniper' who went out of his way to get me a new one, many thanks. I followed the mods the way Bob 'rsterne' laid out so meticulously, but with layman's methods. Since this mod is so readily available on CAF I won't repeat it here.
I would like to tell you though how I managed to get 3 consistent power levels that I can access with no more trouble than removing the air tube.

The first, full power level is essentially the result of the '5 screw mod' with the hammer spring turned 6 times out. Btw, when I opened up the valve seat to 3/16+" the hammer spring didn't have the strength to open the valve adequately. I added a second spring nearly identical to the original but only an inch long into the hammer and the two springs together did the job.

The second, medium power level came from tapping the valve body port with a 10-24 bit, then drilling a 10-24x3/16" set screw lengthwise with a 3/64" drill bit and turning the hammer spring all the way in.

The third, lowest level was attained by using another set screw drilled to a <1/16" hole in the valve body port. Less than because I started with a 1/16" hole and the velocity was still higher than I had planned, believe it or not, so I hammered the hole edges with a drift pin driver until the drill bit no longer fit in. Don't ask me what size it is I don't have many tools.

I'll start with the results of the full power mod that I plan to use for varmint and small game hunting.

HatsanAT44-10long, Full '5 screw mod', HS 6 times out, Jsb 16.2gr .177 cal., 20 shots, 200bar.

1013fps, 1012, 1033, 1035, 1044, 1049, 1063, 1070, 1068, 1072, 1064, 1072, 1071, 1062, 1055, 1056, 1049, 1039, 1031, 1016.

Ending pressure 100bar. Highest velocity-1072fps. Lowest velocity-1013fps. Average velocity-1049fps. Velocity spread-59fps. All within 95% of maximum velocity. Muzzle energy 39.6fp. Not bad for a gun rated at 27fpe. I'll be checking accuracy today and if it's not great I can slow the pellets down by turning the hammer screw in.

Now for the middle power level which I hope to use for 25 and 50m Field Target Shooting.

Same gun,HS 0 turns out,Jsb 10.34gr,Set screw drilled 3/64" in port hole,40 shots,200bar start.

I'm not going to list all 40 shots. Ending pressure 110bar. Started at 905fps and ended at 908fps. Highest velocity 940fps, lowest velocity 905fps. Average velocity 928fps.
Velocity spread 35fps. All within 96% of maximum velocity.

Now for the lowest power level. This is what I'll use in my 10m basement range. You may think that's a short distance for a rifle and I would much prefer getting out to the ranges myself but they're a long drive from where I live. It is however all relative, for instance if you're hoping to shoot, say a 1 MOA spread, then at 50 yards that's about a half inch, so you set up your 10m targets with the equivalent 2.75mm targets (I think). I use a red Sharpie and make dots all over a printer page. If you make it challenging enough you'll get the same buzz when you hit the bulls eye! At this level you only really hear the hammer hit and I can get 100+ shots per fill.

Same gun,HS 0 turns out,Jsb 8.44gr,Set screw with <1/16" in port hole,100 shots,200bar start.

End pressure is about 105bar. Started at 660fps and ended at 648fps after a 100 shots. Highest velocity - 679fps, lowest velocity - 648fps. Average velocity - 667fps. Velocity spread - 30fps. All within 96% of maximum velocity. Who needs a regulator!?

Btw I've thought of a better target for next spring. I'll open the basement windows and rub printer paper with a bloody raw steak to bait fly's lol. That should be a 'buzz'. ;)

_________________
Ed.


Top
 Profile  
 
PostPosted: Thu Dec 24, 2015 7:52 am 
Offline

Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
From so many disasters and setbacks to a better than expected outcome - I couldn't be happier. After the valve body broke in two it was Dan 'sniper' who went out of his way to get me a new one, many thanks. I followed the mods the way Bob 'rsterne' laid out so meticulously, but with layman's methods. Since this mod is so readily available on CAF I won't repeat it here.
I would like to tell you though how I managed to get 3 consistent power levels that I can access with no more trouble than removing the air tube.

The first, full power level is essentially the result of the '5 screw mod' with the hammer spring turned 6 times out. Btw, when I opened up the valve seat to 3/16+" the hammer spring didn't have the strength to open the valve adequately. I added a second spring nearly identical to the original but only an inch long into the hammer and the two springs together did the job.

The second, medium power level came from tapping the valve body port with a 10-24 bit, then drilling a 10-24x3/16" set screw lengthwise with a 3/64" drill bit and turning the hammer spring all the way in.

The third, lowest level was attained by using another set screw drilled to a <1/16" hole in the valve body port. Less than because I started with a 1/16" hole and the velocity was still higher than I had planned, believe it or not, so I hammered the hole edges with a drift pin driver until the drill bit no longer fit in. Don't ask me what size it is I don't have many tools.

I'll start with the results of the full power mod that I plan to use for varmint and small game hunting.

HatsanAT44-10long, Full '5 screw mod', HS 6 times out, Jsb 16.2gr .177 cal., 20 shots, 200bar.

1013fps, 1012, 1033, 1035, 1044, 1049, 1063, 1070, 1068, 1072, 1064, 1072, 1071, 1062, 1055, 1056, 1049, 1039, 1031, 1016.

Ending pressure 100bar. Highest velocity-1072fps. Lowest velocity-1013fps. Average velocity-1049fps. Velocity spread-59fps. All within 95% of maximum velocity. Muzzle energy 39.6fp. Not bad for a gun rated at 27fpe. I'll be checking accuracy today and if it's not great I can slow the pellets down by turning the hammer screw in.

Now for the middle power level which I hope to use for 25 and 50m Field Target Shooting.

Same gun,HS 0 turns out,Jsb 10.34gr,Set screw drilled 3/64" in port hole,40 shots,200bar start.

I'm not going to list all 40 shots. Ending pressure 110bar. Started at 905fps and ended at 908fps. Highest velocity 940fps, lowest velocity 905fps. Average velocity 928fps.
Velocity spread 35fps. All within 96% of maximum velocity.

Now for the lowest power level. This is what I'll use in my 10m basement range. You may think that's a short distance for a rifle and I would much prefer getting out to the ranges myself but they're a long drive from where I live. It is however all relative, for instance if you're hoping to shoot, say a 1 MOA spread, then at 50 yards that's about a half inch, so you set up your 10m targets with the equivalent 2.75mm targets (I think). I use a red Sharpie and make dots all over a printer page. If you make it challenging enough you'll get the same buzz when you hit the bulls eye! At this level you only really hear the hammer hit and I can get 100+ shots per fill.

Same gun,HS 0 turns out,Jsb 8.44gr,Set screw with <1/16" in port hole,100 shots,200bar start.

End pressure is about 105bar. Started at 660fps and ended at 648fps after a 100 shots. Highest velocity - 679fps, lowest velocity - 648fps. Average velocity - 667fps. Velocity spread - 30fps. All within 96% of maximum velocity. Who needs a regulator!?

Btw I've thought of a better target for next spring. I'll open the basement windows and rub printer paper with a bloody raw steak to bait fly's lol. That should be a 'buzz'. ;)

_________________
Ed.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list

Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group

phpBB SEO