Been working on the Bulldog

[tkerrigan]

You can shoot it with just the receiver barrel and air tube by pushing on the trigger thingee.  You probably already know that. 
Regards, Tom

[TheLakeRat]

Roger that! But thanks for mentioning it.

[badgerfarm]

Hi Tom,

I finished my mods to the the Bulldog yesterday and got it put back together but was too late to do any chrony work.  Mine also had the Delrin sleeve in it and I just took it out.  To retain it would take some pretty delicate work and it didn't seem to affect anything.  I ran some 81 gr JSB MKIIs across the chrony today and using 2 turns of preload on the spring and a starting pressure of 2900 psi it ran 920, 970,970, 969, 956 and finished at 2250 psi.  I have some other heavier cast bullets to try and see how they do.  The Bulldog now has a bite.

[tkerrigan]

Great, you can keep turning the spring until it stops, and pick up a bunch more speed.  Regards, Tom

[badgerfarm]

That was exactly the result that I was looking for.  I can dial in the velocity as needed per bullet since the striker preload is so easy to get to.  Thanks for your advice on the mods.

[TheLakeRat]

i finished mine today. i'll try to get a string shot put together today. Last night in my shed i did 3 shots.

started with  790fps and 3rd shot was 820fps. With Mr. Hollowpoints that weigh 143g thats 213.6 Ft/lbs of energy. up from the 177 ft/lbs that i got before.

Super excited to go varmit hunting saturday night.

[TheLakeRat]

OK, had a afternoon off with enough time to run to the range.
Here are my numbers
first string with 143 grain mr. hollow point.
Spring turned in all the way or about 4.5 turns in from stock.
Starting at about 2900psi ending at about 1600psi
826.1
852.9
858.3
846.9
827.0
804.6
789.5
769.4
749.1
729.7

With 95g hp from air venturi
Starting at about 2900 ending at dangit I forgot to look.

983.9
999.2
987.8
957.9
930.8
937.4
907.0
891.7
861.3
829.2

[tkerrigan]

Man, those slugs are moving right along.  Good job.  Regards, Tom

[rsterne]

Nice 5-shot string with the 143gr....

Bob

[tkerrigan]

How's the quiet coming along?  Regards, Tom

[TheLakeRat]

I'm at 83 db. I need a depinger really bad but can't find one and dont really understand how they work well enough to build my own.
I think the ping is 83 db because no matter where I place the meter I still get 83. Under gun on ground. In front of muzzle. On the bench next to me.
I set it in the chrono and it said 81

[rsterne]

The are basically a baffle that fits inside the air reservoir and interrupts the sound wave formed by the valve closing to keep it from bouncing around inside the reservoir, causing the "ping".... They have a couple of problems, which would be worse on a big-bore.... They work better if they have a relatively small hole in them, and if placed too close to the valve, they will reduce the power by decreasing the air pressure in the valve during the shot.... In addition, they tend to creep backwards inside the reservoir towards the valve because of the pressure difference across them during the shot, so need to be anchored somehow to prevent that.... One other thing that can (and has) happened, is that if they are not structurally strong enough, they can come apart, and the pieces can plug the valve, which may mean you think the gun is empty but it still has air in it.... Disassembly under this condition could be fatal.... In the incident I am thinking about, it wasn't, but it blew the reservoir end cap through the ceiling, and left the owner deaf for a few days....

Bob

[TheLakeRat]

Could the tank itself not be surrounded in a sound deadening material such as dynomat?

[tkerrigan]

Is there room for it when the housings are on?  Anything that would stop a bell from ringing would probably work.  Maybe even narrow strips of dynomat with hose clamps tightened around them.  Regards, Tom

[TheLakeRat]

I'll pick some up today but it will probably be a few days before i can get it on.
What about the spring inside? is that something that makes noise? I hear about changing some rod or pin on the marauder that makes less noise. Is that aplicable

Oh and as a side note, i am not using an actual DB meter, just an app on my phone. But i had a reference DB of 108-110 before i began experimenting

[tkerrigan]

Was your reference DB from before the power upgrade?  Might be more of a reduction than it appears.  Regards, Tom

[TheLakeRat]

Reference DB was before any mods at all. I have turned the power back down and it is 1db quieter. for reference i have a 300 blkout that is one of the quietest rifles i've ever shot and it is only 81 - 82 db

[oldpro]

 I have tried about every way a man can try to get accurate DB readings so I will tell you The best way I have found. Put your gun in its firing position and have it ready to fire place your DB meter to the side about 3 feet then cover the DB meter with a folded towl make sure its(DB meter) both to the side and behind the muzzle. 

[tkerrigan]

Hey, if any of you guys make a replacement sleeve with larger ID for the poly in the transfer port, please check FPS before and just after installing it.  Be nice to know if it's worth making one.  My gun doesn't have one but a friend's does and I've been advising him on the bore job and he is wondering about it.  I don't think it will make much difference, but it would be nice to know. I'll make him one if it does.  Regards, Tom

[TheLakeRat]

OK I'm super excited to report that I got my sound deadening material on today and shot the gun 3 times tonight in my Back yard. 76,77,77db.
I still have a loud spring noise in the stock, but I'm not knowledgeable enough to go further.

Here is a pic of where I placed the material. All I had was a 10x11" piece so I made the best use of it I could think of.