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PostPosted: Tue Dec 02, 2014 12:16 am 
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I won't be crimping an all brass shell.... The overshot card I have is cardboard, not plastic, and is snug in the mouth of the brass....

Bob

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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!


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PostPosted: Tue Dec 02, 2014 12:33 am 
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rsterne wrote:
I won't be crimping an all brass shell.... The overshot card I have is cardboard, not plastic, and is snug in the mouth of the brass....

Bob


So your not looking for a "card" to keep the balls or shot in place? I guess I am not understanding what you need? I reloaded from the time I was 15 till I was 40. Pretty damn good at it.

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PostPosted: Tue Dec 02, 2014 9:14 am 
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Bob if you have a problem with your cardboard card falling out try 1-1.5mm cork. This is what I use upon my CR1100 shot shells. Make a hole punch for the cork. Once its inserted it slightly expands and holds very well. It just might be a bit of experimentation to find the right item.

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PostPosted: Tue Dec 02, 2014 11:58 am 
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The card is nice and tight, especially when new.... The one in the photo has been inserted and removed many times and will still hold the shot in place, although maybe not if you drop the shell.... Here is a photo of it in place....

Image

Good idea with the cork, Kim, if I have a problem I'll try that, but I have a box of 500 of the card wads and they seem to work fine.... The brass shells are thinner than paper, so the wads are slightly larger, they are made as an overshot card for that specific casing.... very tight when new.... I suppose the cork might break apart on firing and eliminate holes in the pattern, however....

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!


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PostPosted: Tue Dec 02, 2014 2:14 pm 
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Location: Victoria, BC and Clarkston, WA
Whitewolf wrote:
Bob if you have a problem with your cardboard card falling out try 1-1.5mm cork. This is what I use upon my CR1100 shot shells. Make a hole punch for the cork. Once its inserted it slightly expands and holds very well. It just might be a bit of experimentation to find the right item.


I have a big roll of 1/16" cork if need be Bob or Kim

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-Rick
Pardini K10
Brocock Concept .22
3 Custom Crosman 2260
Benjamin Discovery .22 w/Joe Hickey stock!
Crosman 150 pistol .22
4 Crosman MK 1 pistol .22
Mrodair CP-1M .22 and .177


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PostPosted: Tue Dec 02, 2014 4:32 pm 
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rsterne wrote:
The card is nice and tight, especially when new.... The one in the photo has been inserted and removed many times and will still hold the shot in place, although maybe not if you drop the shell.... Here is a photo of it in place....

Image

Good idea with the cork, Kim, if I have a problem I'll try that, but I have a box of 500 of the card wads and they seem to work fine.... The brass shells are thinner than paper, so the wads are slightly larger, they are made as an overshot card for that specific casing.... very tight when new.... I suppose the cork might break apart on firing and eliminate holes in the pattern, however....

Bob


For all the shells I've fired never noticed as to whether or not the cork broke apart. Main concern was shooting that grouse.. :shock: ..lol. Heck if the reloading cards work :D no sense changing it till you run out.

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PostPosted: Tue Dec 02, 2014 4:45 pm 
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If I go through 500 wads and shot cups, even with testing, I'd be shocked.... *LOL*.... I have 25 brass and 25 lbs. of #8 shot (enough for 800 loads).... I'll use the cards unless they blow holes in the pattern.... if they do, I'll try the cork....

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!


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PostPosted: Wed Dec 03, 2014 6:42 pm 
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I love your technical knowledge and ability to attack these projects with thought, science, and skill to create such awesome airguns!!


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PostPosted: Wed Dec 03, 2014 8:54 pm 
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Today I took the valve out, replaced the 70D O-ring that had a slow leak with a 90D, filled the gun from my new Great White, took out my hearing aids, put in my earplugs, and fired the first shot.... Yup, it's pretty loud!.... I had the hammer spring preload at maximum, and at 3600 psi it was just under 800 fps with three 000 Buck.... Not as strong as I was hoping for, but nearly 300 FPE, the most powerful shot I have ever had from an airgun.... I fired a few shots and examined the plastic shot cups I found down by the backstop, and they were all split or blown open through the middle of the base.... I wondered if possibly I was getting a lot of blowby, so I used a 1/4" thick fibre wad in the shell first and then the three Buckshot (no shot cup), and got more consistent and higher velocities.... The highest I saw was 817 fps, and that was 7 yards from the muzzle, so that corrects to 833 fps at the muzzle (313 FPE) at just under 3000 psi.... I got 7 shots from 3600 psi down to 2700 within 4% ES....

The disappointing part of the first tests was that I don't have enough hammer strike.... I got a very nice shot string, but I'm maxed out, and the peak is at just under 3000 psi.... This is despite having a 237 gr. hammer with 2" of travel and a spring that takes 36 lbs. to cock.... and a PEEK valve.... Before I make any changes I will try the .457 Rifle barrel with some 220 gr. bullets I have, and some roundball, just to get a baseline.... I have no idea how I could increase the hammer strike if I need to, to get more power....

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!


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PostPosted: Wed Dec 03, 2014 9:08 pm 
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Hmm, it's not like 300+ fpe is exactly bad. If you settled for that I'd still call it a roaring success. But I know you'll want to see how far you can take it, just for the challenge :)

Looking forward to hearing the results with the rifle. Thinking of which, how's your backstop holding up to the abuse? I have an amusing image of doing penetration tests with this thing - "we're going to need some more soap!"

Jim


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PostPosted: Wed Dec 03, 2014 9:44 pm 
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I rebuilt my backstop before this round of testing.... It is a wooden box 12" x 16" inside, with a 3/16" steel plate in the back, and 6 layers of OSB in front of that, and then a couple of layers of cardboard on the front to hold the target.... With enough use the OSB turns into a pile of chips on the floor.... I've never used it for anything at this power level before, so I'm keeping a close eye on it.... and I have three 32" x 48" pieces of 3/4" plywood behind it as a shield for the wall in case anything ever goes through....

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!


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PostPosted: Thu Dec 04, 2014 2:44 pm 
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Bob, would you be able to add lead to the core of your hammer design to increase the mass?

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PostPosted: Thu Dec 04, 2014 2:53 pm 
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Bob, what's the ID of the gas tube? I have a very crazy idea for your hammer :)


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PostPosted: Thu Dec 04, 2014 6:00 pm 
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It turns out I had another hammer spring here to try, which allowed me to examine what the maximum performance was.... It was actually two 3" long springs of 0.062" wire instead of the single 4.5" long spring of 0.072" wire.... This gave me about the same force when cocked, but instead of having no preload when uncocked it had a preload of about 10 lbs.... That gave more hammer energy, so I was able to find out where the velocity plateau was at 3600 psi.... It turns out the gun maxes out at about 870 fps (340 FPE).... I couldn't back the preload adjuster out far enough with the long spring to get down under 800 fps, but by using the original spring I was able to plot the velocity profile.... Once I established that the best place to tune the gun was with the original spring maxed out, I then shot a string, recording all the shots within 5% of the peak....

Image

The best choice for a hammer spring would be one about 5" long, made of 0.062" wire, and I can get a 10" one from Trakar and then cut it in half, which is the eventual plan.... However, I was able to get 9 shots with 5%, of which 7 shots were within 3% ES.... The average velocity for those 7 shots was 819 fps (302 FPE), and I would refill at about 2500 psi, and the efficiency is 0.76 FPE/CI....

I think this will prove to be an effective short range Grouse gun.... It doesn't have the smack of a powderburner, but if I can get decent patterns with the #8 shot I think it will do the job....

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!


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PostPosted: Thu Dec 04, 2014 8:52 pm 
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great work as usual Bob :wink:

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