Canadian Airgun Forum

The #1 Community for Airguns in Canada!
It is currently Fri Nov 15, 2019 3:28 am

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  [ 27 posts ]  Go to page Previous  1, 2
Author Message
PostPosted: Tue Jan 06, 2015 3:09 am 
Offline
User avatar

Joined: Wed Oct 17, 2007 3:27 am
Posts: 2586
Location: Winnipeg, Canada
Whitewolf wrote:
Doc Sharptail wrote:
Chevota wrote:
The JSB 13.43gr are excellent, so if you haven't tried them I'd check 'em out.


Those are a new one on me. I've tried the JSB 10.3 and they don't stand up to the crosman premier ultra mags in the crosman bbls I've tried them in.

Which Chevota is it? Dakota 350 4 bbl?How about a 360, aka 5.9L... :lol: Wonder why I was thining of a small block chev in a Dakota :lol: :wink: Or a chevette with a 2 litre 'yote under the hood?

Regards,

Doc Sharptail

_________________
"Ain't no half-way"
-S.R.V.


Top
 Profile  
 
PostPosted: Tue Jan 06, 2015 5:48 pm 
Offline

Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
@rsterne Thank you, sir, for those links! I thought of a question to ask you, today. The barrel/barrels that you shot the .177 caliber Rabbit Magnum IIs through, are/were these choked barrels?


Top
 Profile  
 
PostPosted: Tue Jan 06, 2015 7:32 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8974
Location: Coalmont BC
Nope, not choked, AFAIK....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


Top
 Profile  
 
PostPosted: Wed Jan 07, 2015 2:52 pm 
Offline

Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
Bob,
Did you use the advertised 15.74 gr parameter for calculating your results ? I've read a couple of occasions where the .177 Rabbit Magnum IIs actually weigh 16.1 gr. Do you have a way to weigh these ? I no longer have a scale of this type, myself. I'm just wondering what the numbers would be if indeed these do actually weigh 16.1 gr. I also checked into getting a custom twist Polygon Lothar Walther barrel, but for custom rate of twist there is a "minimum 5-10 barrel order." I think that the Polygon rifling, instead of regular cut rifling may help a lot towards achieving accuracy with these R-M-IIs.


Top
 Profile  
 
PostPosted: Wed Jan 07, 2015 3:33 pm 
Offline
User avatar

Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8974
Location: Coalmont BC
Mine are 16.4 gr.... I didn't bother using the weight in my original calculations (I used pure lead, see below).... Correcting for that weight reduction, which results in a average SG of 10.0 instead of 11.4, with a 16" twist, I get the following stability factors with a 16" twist.... 1.6 @ 500 fps, 1.4 @ 800, 1.3 @ 900, 1.1 @ 1050, and 1.00 @ Mach 1.... Still not a problem in a 16" twist up to at least 900 fps, but if you plan on pushing them faster you should consider a 15" twist.... That would give you SF = 1.3 @ 1050 fps.... A 14" twist would be SF = 1.5 @ 1050 ad 1.3 @ Mach 1, based solely on the weight correction.... and would not be "too fast", IMO....

Sorry I didn't use the weight correction originally.... but in fact it's not as drastic in real life as the above numbers indicate for the Rabbit Magnum because the reduction is weight is primarily in the hollow base, which is closer to the centerline, and the mass around the outside edge is nearly as great as if the bullet was solid lead (SG = 11.4).... Therefore the correct numbers will actually be in between these numbers and what I posted initially, and closer to the originals as the moment of inertia when spinning is most influenced by the mass around the outside of the bullet....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


Top
 Profile  
 
PostPosted: Thu Jan 08, 2015 2:40 pm 
Offline

Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
Bob, Thank you, again, for all of your help here! Much of what you have written is over my head, but I'll research until it all makes perfect sense to me.

Owen


Top
 Profile  
 
PostPosted: Mon Jan 19, 2015 3:49 pm 
Offline

Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
Negotiations with Lothar Walther for a single polygon rifled, 1:15" twist barrel have fallen through. I only have one .177 caliber air rifle, a Crosman storm XT, so I checked and it's rate of twist is 1:15.935" (1:16"). The rifle I'm wanting to shoot the .177 Cal. Rabbit Magnum IIs with is a Benjamin XL1100, which is presently a .22 cal. I have ordered a .177 cal. barrel for the XL1100, hoping it too is 1:16". If it's not, then I'll order a Storm XT barrel and fit it. I really want the Lothar Walther, but that just doesn't seem to be a viable option. Also, after much reading about the subject of swaging airgun bullets, the Russian forums are the greatest source of information, the Rabbit Magnum IIs may not be exactly what I'm wanting. I may have to make my own custom mould. The Nomad Pellet Maker may also be a great option, if it can be made to a custom specification.


Top
 Profile  
 
PostPosted: Mon Apr 13, 2015 6:15 pm 
Offline

Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
I finally got around to shooting some of the .177" Rabbit Magnum IIs through this Benjamin XL 1100, with a .177" barrel. By the way, the rate of twist of this barrel is 1:16.5". The results were dismal, 2.5" @ 43 yards. I've also been shooting the 16.2 gr JSB Beasts, which I've seen 1/2" groups @ 43 yards with these in the .177" XL 1100. According to one Russian shooter, the JSB Beasts are giving him a ballistic coefficient of .047. His gun is a PCP and it is probably more powerful than the rebarreled XL 1100. I did buy yet another .177" gun to try both of these heavy pellets with. It's a Hatsan Torpedo 155 and it's pushing both of these pellets much harder than the XL 1100. Rabbit Magnum II's are grouping 1.5" @ 43 yards, while the JSB Beasts have given even 1/4" groups! This is with a spring, a J. Macarri piston seal and a home made breach seal. I've ordered some fully enclosed face piston seals, breach seals and a gas-spring, from airmagnum.ua, Rivne, Ukraine, but these have not arrived yet. With the spring the JSB Beasts are averaging 827fps for 24.6fpe. With todays atmospheric conditions, @ 121 yards the Beasts are still delivering 13.56fpe. I'm expecting to get some more power from the gas-spring and closed face seals. I'll also increase accuracy by bushing the rear of the barrel. Will update then.
https://www.dropbox.com/s/8v711yt01wqxram/IMGP0747r.jpg?dl=0
https://www.dropbox.com/s/ppyv00tsrw2zdsz/IMGP0752r.jpg?dl=0


Top
 Profile  
 
PostPosted: Tue Apr 14, 2015 2:20 am 
Offline

Joined: Sat Jan 25, 2014 9:16 pm
Posts: 1271
Location: United States
Very interesting on the JSB Monster, glad they work so well. Crazy BC as well, diggin it. No surprise on the Rabbit, most everyone gets the same results and doesn't look springer friendly at all. I just bought some Monsters but haven't tried them yet, and they were out of stock on the new Barracuda Mags :(
What was the power of the XL before and after the new barrel, which is how long now? My guess is that short would kill it, but I wonder by how much? I was assuming a choked Lothar since you mentioned that before, but that twist doesn't sound right. Let me know please because I've been wanting to Lothar my XL and/or Diana 350, and was curious about things like if you were you able to get Lothar to machine it to fit the block, or if another brand then what's the deal? Thanx...


Top
 Profile  
 
PostPosted: Sat Apr 18, 2015 12:03 pm 
Offline

Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
The XL 1100, in .22, was averaging about 27fpe shooting JSB 18.13s. In .177, with 16.2gr JSB Beasts, it's averaging less than 21fpe. I do not know if Walther offers maching services. The .177 barrel that you see in the image is from Crosman/Benjamin, cut off at the muzzle end to 11.25" length.


Top
 Profile  
 
PostPosted: Sun Apr 19, 2015 6:04 pm 
Offline

Joined: Sat Jan 25, 2014 9:16 pm
Posts: 1271
Location: United States
Oic. So when you said rebarreled you meant going from oem 22 to oem 177. Still I would've never guessed it could shoot 21fpe with that short 177 bbl, I would've guessed more like 18. Are you going to put the .22 bbl back on? My 1100 is shooting those same 18.3's at 28, but I'm probably at a lower elevation (~800'/250m).
I'm curious about that enclosed main seal, which I assume is this guy?: http://io.ua/29379853
Looks like is has potential but hard to tell from that pix. Maybe I'll offer them a decent camera in exchange for parts. I didn't see any dimensions listed so I wondered if you could tell me what it's meant to fit (I can't read Ukrainian)? I use a Maccari Walther Talon seal on my XL which I think would be hard to beat, but that enclosed looks like it has potential. Mosty I'm looking for a good 28mm seal for Diana guns, which I have yet to find. Not that I've tried a lot, but if you have an opinion... I bought a Vortek Proseal28 a while back which is just awful, I won't even try it. Tried their O-ring seal but looking for better. Thanks.


Top
 Profile  
 
PostPosted: Thu Apr 23, 2015 4:01 pm 
Offline

Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
Yes, those are the piston seals that I was reffering to. I've had one in a Hatsan 135, .22 caliber, for over 1.5 years. I put it in the rifle, and an Airmagnum gas-piston too, in the fall of 2013 and after 500 or so shots I chronographed it, on a -2C day. It averaged 864fps/30.04fpe, for 18.13s. In the summer it averaged somewhere around 875fps, 875 or 877 I can't remember, for 31fpe. In the fall of 2014 I noticed that the temperature was -2C so I chronographed the rifle and it was, again, averaging 864fps/30.04fpe. That was one year later and around 6,000 shots after chronographing it the first time. I think that these are good seals.
No, I have many things to try before giving up on the .177 caliber XL 1100. The Rabbit Magnum IIs are not going to work in this barrel though, because it slugs at .178"/4.52mm. The .177 caliber Walther barrel, the polygon version anyway, is supposed to slug .181"/4.597mm. That would probably work very well with the Rabbit Magnum IIs.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 27 posts ]  Go to page Previous  1, 2

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:  
cron
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