450 Bush Comps

[bmosely]

With the lack of options over the Izzy, I am in the process of fitting a JP Bennie Coolie and a JP Recoil Eliminator comp to the .450. For anyone else interested in these options, I thought I would share the specs. A lathe is required to make sure the threads and bore holes are true, so I had to enlist a gunsmith for the rethreading and hole enlargements.

The barrel on the .450 is .750 O.D. with the barrel threaded at 11/16 x 24 pattern. There are several options in sizes for these comps, but the .750 o.d. model leaves too little material after threading to 11/16". The minimum size is .875" o.d. or the .925" o.d.. While this leaves a small step in the finished product, the Izzy does not sit flush as the crush washer is bigger than the barrel o.d. anyway. I wanted the black versions which limits some of what you can buy. Getting the 1/2"x 28 for the .223 version leaves the most material to drill and retap but the 5/8" x 24(.308) will also work. The 3/4" thread version will not work. I contacted JP about suppling these models for the .450 but they do not and will not cut them custom.

The models I used are: 5.12B.925 and JPRE-428.

The specs are: Threads 11/16 x 24
Min. exit hole .492"
Min. Intermediate hole .575"
Max. Intermediate Hole .678"

The exit hole is per JP specs, and the inter. holes are based on reviewing the different models and comparing how they are sized. I am not sure why the intermediate hole varies in the different calibers, but it does.

Bushmaster is the only source for crush washers, but a 5/8"(.308) model can be opened up to 11/16" to work.

This is where it sits. Hopefully I will have them back next week and can give a range report. The comp. at $100 from Midway and the tooling look like $125 out the door for each. I am not sure if there is interest at this number, but I would like to hear feedback.

http://www.midwayusa.com/viewProduct/?p ... ber=779850
http://www.midwayusa.com/viewProduct/?p ... ber=603848

While the eliminator looks like a tennis ball on the computer, it is not that big in reality. It should really knock the recoil down.

I have them back, but have not shot yet. Let's see some warm weather!

[Al in Mi]

very interested to see what both do for recoil.

thanks for sharing.

[Siringo]

I saw a video -- of all the places -- on the local news -- about JP's Comp. Guy put a 270 up to his chin and shot it. Nothing! They seem to work well. Are you going to shoot a video so we all can see!!!!!

[BD1]

This is the custom Gentry "Quiet brake" on my .450B. A smith in NY who was working with gentry on shotgun brakes had it made for me and did the drilling, tapping and fitting. I'm sure that it's not as effective as as a "tank" brake like the JPRE, but it's effective enough and it is much easier on my ears when hunting. For this design to be effective, the tolerances are a little tighter. the brake is bored .455.
BD

[Colohunter]

I'm interested in how these shoot, I am sure they will knock down the recoil quite a bit. Also let us know how much the sound a muzzle blast appear to change, both for the shooter and from standing to the side.

[BD1]

It would be fun to sit down and do a side by side comparison of different brake designs using the same rifle and load.
BD

[gunnut]

Let me know where and when you would like to do this! I do have a way of measuring and record both the recoil and sound levels

[wildcatter]

Let me know where and when you would like to do this! I do have a way of measuring the effect.

Ok Guys, if your going to keep going down this line, you'd better listen to the Gunnut, and pick his brain dry. Right now he pretty much "IS" the repository of knowledge concerning these matters vs recoil reduction and this diffidently includes Brakes..t

[BD1]

I'm near Savannah and shoot at a range in Ridgeland, SC. Let's see how many designs we can come up with and decide on a range central to those participating?
BD

[gunnut]

Thanks WC..I'm on the North East side of Atlanta. Any place within a day's drive round trip would be fine with me. Don't forget the ammo and crush washers.