Tuning Crosman DPMS SBR build

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Bedsidemanner said:
Cool, Naw I'm still trying to get my magazine mod to work. Had some issues with PAir. bad bottle and hose, two separate returns. during the down time I have been playing with heated CO2 and broke my hammer pin, replaced it with a steel bolt next day. I have been getting better numbers from the CO2 than the bottle at 1100 regulated.
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Man that sounds so cool bro. Let me ask tho what's the Best place to start on the gun like what peices to upgrade first..
 
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JoeyJohnson said:
Actually I just put a ton more into it. It now has:

Even heavier hammer spring system.
Completely rebuilt breach and inner and outer barrel with a 20 3/8 in inner barrel.
4500 psi tank with picatinny mount
Adjustable regulator to shoot from 1000psi ( with factory hammer spring ) for plinking or up to 3k psi per shot. But I find they shoot best at about 2500psi

And honestly alot more that I really don't feel like typing. :)

I also built my wife a an A4P which is really the exact same gun but with a different stock setup. Both can move steel 5.1 g bbs at 1650 fps and I can push 10g nickle platted lead shot at close to that which is about 60ft lbs of energy per shot. I got a bb through a steel frying pan so thats pretty good.
All semi auto and full auto still works correctly. I have put about 500 rounds through them both and everything is holding together well.

If anyone is interested in this I was thinking of putting a kit together to convert a stock one to a PCP air gun. Please direct message me for pricing and other details.

Thanks!

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View attachment 300406Love your set up you have there. I wanted to start my magazine mods to get more psi out of my DPMS SBR . Can you help me to get started on it . Do I need a heavier hammer spring and can I just drill out my valve a little. Thanks
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RM3Miller said:
Hi, anyone run into this problem? My DPMS SBR old magazine and brand new one. When I shoot it gets stuck on full auto with out even hitting the trigger. Everything is stock on it . Any thing to check out on it ? Thanks
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Look up RumbleCanada on YouTube, I saw a video that he did. You have to drill out the rubber seat for the barrel so the BB can easily fly out.
 
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Go on Aliexpress and get the CO2 to HPA conversion kit, as of last year I bought both RG / STW versions for $14 and got free shipping. You will have to fill down or chamfer the ends of the cartridges a bit to get them to fit into different mags. The RG doesn't fit into the dpms or my paintball version one, but the STW can with two nuts on either side. ANT has a patent on these designs, so you can't really buy them in the US, if you're going to use this a lot just buy from them. Otherwise, I got a .5L Ninja 3000psi reg @ 800psi for $10 on ebay from an open box return, the thing is literally new, and hose adapter on Amazon. It's all pretty cheap conversion for under $50. The only thing that I don't like is you have to keep shooting the gun 20 times to release the pressure in the hose when you want to disconnect.
 
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JoeyJohnson said:
View attachment 124764

Just wanted to reach out to everyone and let you know I just finished doing a build on a Crosman DPMS SBR. I wanted to post this because I have not found any other info on this gun anywhere online. This also motived me to do this build. I did a sevral mods on it, including -

  1. Two stage hammer spring system
  2. Conversion to HPA regulated at 1100 psi
  3. REAL silencer made from mock suppressor
  4. Polished hammer bolt
  5. Rubber upper and lower support bushings
  6. Red dot sight
  7. Real iron alternate sights with quick use
  8. Many other cosmetic items
    [/LIST=1]

    If any body has any questions on this gun I know it inside and out. I would be happy to help anyone else who might be doing mods on this gun. I ran it over a chrony and I am just about at 1000fps. It hits pretty damn hard in full auto. Now if I could just figure out how to build a 100 round clip. :)




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Hi,I am starting to mAke mods on my dpms sbr .you have mentioned two stage hammer spring system.do you have any pictures of it .? Or where to buy it from.I have a lot of magazine parts.I went right to the source and found that I vy
JoeyJohnson said:
View attachment 124764

Just wanted to reach out to everyone and let you know I just finished doing a build on a Crosman DPMS SBR. I wanted to post this because I have not found any other info on this gun anywhere online. This also motived me to do this build. I did a sevral mods on it, including -

  1. Two stage hammer spring system
  2. Conversion to HPA regulated at 1100 psi
  3. REAL silencer made from mock suppressor
  4. Polished hammer bolt
  5. Rubber upper and lower support bushings
  6. Red dot sight
  7. Real iron alternate sights with quick use
  8. Many other cosmetic items
    [/LIST=1]

    If any body has any questions on this gun I know it inside and out. I would be happy to help anyone else who might be doing mods on this gun. I ran it over a chrony and I am just about at 1000fps. It hits pretty damn hard in full auto. Now if I could just figure out how to build a 100 round clip. :)





Click to expand...
 
Upvote 0
JoeyJohnson said:
View attachment 124764

Just wanted to reach out to everyone and let you know I just finished doing a build on a Crosman DPMS SBR. I wanted to post this because I have not found any other info on this gun anywhere online. This also motived me to do this build. I did a sevral mods on it, including -

  1. Two stage hammer spring system
  2. Conversion to HPA regulated at 1100 psi
  3. REAL silencer made from mock suppressor
  4. Polished hammer bolt
  5. Rubber upper and lower support bushings
  6. Red dot sight
  7. Real iron alternate sights with quick use
  8. Many other cosmetic items
    [/LIST=1]

    If any body has any questions on this gun I know it inside and out. I would be happy to help anyone else who might be doing mods on this gun. I ran it over a chrony and I am just about at 1000fps. It hits pretty damn hard in full auto. Now if I could just figure out how to build a 100 round clip. :)




Click to expand...
Hi , I am starting to do mods to my dpms sbr.was wondering if you have any pics of the two stage hammer spring system.or where can I buy them at.I have a lot of magazine parts.I got lucky and went right to the source for any new magazine parts.I bought #10 new valves ,15 springs ,and 15 sets of seals.
JoeyJohnson said:
View attachment 124764

Just wanted to reach out to everyone and let you know I just finished doing a build on a Crosman DPMS SBR. I wanted to post this because I have not found any other info on this gun anywhere online. This also motived me to do this build. I did a sevral mods on it, including -

  1. Two stage hammer spring system
  2. Conversion to HPA regulated at 1100 psi
  3. REAL silencer made from mock suppressor
  4. Polished hammer bolt
  5. Rubber upper and lower support bushings
  6. Red dot sight
  7. Real iron alternate sights with quick use
  8. Many other cosmetic items
    [/LIST=1]

    If any body has any questions on this gun I know it inside and out. I would be happy to help anyone else who might be doing mods on this gun. I ran it over a chrony and I am just about at 1000fps. It hits pretty damn hard in full auto. Now if I could just figure out how to build a 100 round clip. :)





Click to expand...
 
Upvote 0
mprescott said:
Go on Aliexpress and get the CO2 to HPA conversion kit, as of last year I bought both RG / STW versions for $14 and got free shipping. You will have to fill down or chamfer the ends of the cartridges a bit to get them to fit into different mags. The RG doesn't fit into the dpms or my paintball version one, but the STW can with two nuts on either side. ANT has a patent on these designs, so you can't really buy them in the US, if you're going to use this a lot just buy from them. Otherwise, I got a .5L Ninja 3000psi reg @ 800psi for $10 on ebay from an open box return, the thing is literally new, and hose adapter on Amazon. It's all pretty cheap conversion for under $50. The only thing that I don't like is you have to keep shooting the gun 20 times to release the pressure in the hose when you want to disconnect.
Click to expand...

JoeyJohnson said:
View attachment 124764

Just wanted to reach out to everyone and let you know I just finished doing a build on a Crosman DPMS SBR. I wanted to post this because I have not found any other info on this gun anywhere online. This also motived me to do this build. I did a sevral mods on it, including -

  1. Two stage hammer spring system
  2. Conversion to HPA regulated at 1100 psi
  3. REAL silencer made from mock suppressor
  4. Polished hammer bolt
  5. Rubber upper and lower support bushings
  6. Red dot sight
  7. Real iron alternate sights with quick use
  8. Many other cosmetic items
    [/LIST=1]

    If any body has any questions on this gun I know it inside and out. I would be happy to help anyone else who might be doing mods on this gun. I ran it over a chrony and I am just about at 1000fps. It hits pretty damn hard in full auto. Now if I could just figure out how to build a 100 round clip. :)





Click to expand...
How do you drill extra holes in the valve? I already messed up two valves
 
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