450B upper build question

[Clipity]

I have been going back and forth on building a 450 bushmaster but can't figure out something. I have seen that a few people have built these, but what I haven't seen what kind of upper is being used other than someone said they used a DPMS. So what works A3 with A3 feed ramp, A3 with M4 feed ramp or A2? I have read that when building a 50 Beowulf they say not to use uppers with the M4 feed ramp anyone know why?

TIA Clipity

[2zero6]

I have been going back and forth on building a 450 bushmaster but can't figure out something. I have seen that a few people have built these, but what I haven't seen what kind of upper is being used other than someone said they used a DPMS. So what works A3 with A3 feed ramp, A3 with M4 feed ramp or A2? I have read that when building a 50 Beowulf they say not to use uppers with the M4 feed ramp anyone know why?

TIA Clipity

The Barrel extension is ground down to center the rounds fed as the projectile is much larger in diameter. If you use a Mil spec upper receiver you will need to enlarge the ejection port. There is a very well put together how to by the the_mad_rshn found here: http://450bushmaster.net/viewtopic.php?f=2&t=132 .
There is also another good thread found here: http://450bushmaster.net/viewtopic.php?f=2&t=104
Bushmaster's part number for their upper receiver less barrel/extension and BCG is: VUR-45 is for a .450 upper reciever (includ. forward assist, factory .450 laser printing, and dust cover) price $190.00 before shipping.I believe MGI also sells .450 parts as well, Even the barrel is Bushmaster stamped. That thread can be found here: http://450bushmaster.net/viewtopic.php?f=2&t=887. Hope all this helps.

[Mike]

Another option on the ejector port is to send it to me with enough money for me to ship it back and Ill mill the port out for you. I personally like the lopro slick side uppers as they lack a forward assist which keeps you from turning a bad situation into a worse situation.

[2zero6]

Unless you want the forward assist to close the bolt a little quieter in certain hunting situations. Mike, didn't you use some MGI parts?

[Mike]

Quite a bit ........ Just got a couple more sumthin sumthins from them ......Man I wish they sold a 20 ".


2Zero- Just for you Im gonna do a side charger next go round. That would be the best of both. You think I should go left or right side???? I just need to find a teeny tiny skull to fab into the charging handle, Titanium preferably, but Ill settle for steel.................. LMAO

[2zero6]

2Zero- Just for you Im gonna do a side charger next go round. That would be the best of both. You think I should go left or right side???? I just need to find a teeny tiny skull to fab into the charging handle, Titanium preferably, but Ill settle for steel.................. LMAO

I would love to do a left side bolt/right side ejection side charger (like the LWRC REPR) to be able to keep firing grip maintained. I always thought that layout made much more sense ergonomically and tactically. On a lighter note you could always make a trip to the local auto parts store and get those little skull tire valve stem caps or skull lock knobs.

[Mike]

Holy Crap that would be worth doin just to have the pictures. Ill get the ones with the internal battery and LED eyes that light when its in motion. that would be hot.

I couldnt agree with you more on the lefty charger. You got any parts to donate to your cause? Spare upper? carrier?

Speaking of carriers- does anyone make one anymore without the dust cover recess? I know they are makin them wthout the FA serrations, But the ones Im finding still have the recess.

I cant remember where I saw one, but my latest attempts are turning up with nothing.

[2zero6]

Closest thing I remember seeing is JP Enterprises low mass bolt carrier . I would actually keep the recess as to help channel out dirt and contaminants (in theory).

[Clipity]

Loving the thread jacking going on here.

[2zero6]

Loving the thread jacking going on here.

Sorry, won't happen again. As far as the feed ramps go, if you are modding your own extension you will need to grind down the lower part of the extension where the feed ramps are and make it into a larger single feed ramp. Hope that helps.