450 bushmaster

[wvlapua]

I'm putting together a 16" 450bm and can't decide on a stock, RE, buffer combo. It will be primarily a hunting rifle for stalking. I originally wanted to run an STR on a carbine length RE with heavy buffer. Then I changed my mind to Vltor A5 system with STR. Now I thinking just go fixed either a MOE fixed rifle length, Vltor Arm, or RRA operator A2 with MGI RRB and Wolf XP spring.

It has carbine length gas with a .093" gas port, 16" barrel. If you have experience in this caliber or with these components on a thumper, please give your input/suggestions.

 

[jasonfaz]

What's causing you to change your mind? I'd go with the A5/STR combo to smooth out the recoil impulse without adding a bunch of length. Then again, if you don't mind the additional length the A2 would be good as well. I prefer Slash's 308 springs (which he can cut to whatever length you end up needing) over the Wolff or SpringCo XP springs. I'd also go with a heavy buffer. I use the 8.5 oz buffer from Slash in a 8" 458 w/pistol gas and am very pleased with how well it shoots and cycles. Might even look into their A5 length buffers.

 

[wvlapua]

That was my original thinking..but was unsure if the A5 system would tame recoil like a fixed A2. I actually emailed Vltor back and forth and they were unsure how well it would work. Although i don't see why it wouldn't. Thank you for your input.

What's causing you to change your mind? I'd go with the A5/STR combo to smooth out the recoil impulse without adding a bunch of length. Then again, if you don't mind the additional length the A2 would be good as well. I prefer Slash's 308 springs (which he can cut to whatever length you end up needing) over the Wolff or SpringCo XP springs. I'd also go with a heavy buffer. I use the 8.5 oz buffer from Slash in a 8" 458 w/pistol gas and am very pleased with how well it shoots and cycles. Might even look into their A5 length buffers.

 

[jwb47]

I used a moe rifle stock on my beowulf with a mdt recoil pad . it works pretty good .

 

[wvlapua]

Nice..how's the cheek weld on the MOE?

I used a moe rifle stock on my beowulf with a mdt recoil pad . it works pretty good .

 

[jwb47]

the cheek weld is the same as an a2 stock . One thing to consider Is A big bore with an adjustable stock can cause some odd issue's . I have a 458 socom with a moe crt stock on it and if you have facial hair at times it will remove it . this is why I no longer have a beard . having two of the big three I really dont think there is a hill of beans difference except the name and case configuration , they all produce about the same down range energy so dont get caught up in the my dogs better than your dog debate . at some point I am going to build a 20 inch 450 bushy just because I like things a bit different .

 

[wvlapua]

Thanks..the facial hair issue is the reason I have migrated away from the Vltor arm stock. Looks like it could bring tears.

Now I'm curious how the MGI RRB in a carbine length RE would stack up against the Vltor A5 system. Wonder which setup would effectively reduce more recoil?

The 20" 450bm that bushmaster sells is still carbine length gas. It just has a second dummy gas block at the rifle length position. Seems a little odd to me. Surely they at least tried mid and rifle length gas in R&D. 450bm not being over gassed must bear some truth. This is the reason I went 16".

the cheek weld is the same as an a2 stock . One thing to consider Is A big bore with an adjustable stock can cause some odd issue's . I have a 458 socom with a moe crt stock on it and if you have facial hair at times it will remove it . this is why I no longer have a beard . having two of the big three I really dont think there is a hill of beans difference except the name and case configuration , they all produce about the same down range energy so dont get caught up in the my dogs better than your dog debate . at some point I am going to build a 20 inch 450 bushy just because I like things a bit different .

 

[jasonfaz]

I tried KynShot's std 308 buffer (same 3.25" length as std ar-15 buffer with a heavier dampening mechanism up front) and a JP SCS with 85# and 90# springs in this 14.5", carbine length .458.

While I really like the KynShot compared to other hydraulics, I did not feel it was even close to the JP after adjusting spring tensions and slightly adjusting gas in a std carbine length RE. I ended up moving the upper over to a lower with an A5 and A5H4 (6.83oz) installed. That proved to be the ticket as the A5 allows for the same length of travel as does the A2 set up which translates into a longer, smoother recoil impulse.

The least recoil I've ever been able to get was in an 18" .458. I had SBR Ammunition make me a custom pipe with an intermediate length gas system and .0972" gas port back in 2011. That was prior to my experimenting with the A5 system and, hence, used an A2 and std weight buffer. That rig barely moved when I shot it, incredibly smooth. Got me a bull Elk at 230yds that year with a hot 350 gr TSX load...

At the end of the day, if I were building another carbine length, 16" big bore, I would absolutely use the A5 and either the A5H3 or A5H4 weight buffers. I'd go STR because 1. it locks and won't move under 'heavier-than-5.56' type recoil; and 2. it's the only adjustable stock that I'm aware of that will fully collapse on an A5 tube and that's generally how I prefer to shoot in any offhand firing position. The cheek weld is, IMO, much better on the STR over the CTR and certainly more beard friendly!

 

[3GunRunner]

how about an adjustable gas block to help control the beast as well?

 

[wvlapua]

You sir are the man..nice looking rifles. I will take your advice and learn from your experience. Thank you. A5/STR with Slash's 308 springs.

I tried KynShot's std 308 buffer (same 3.25" length as std ar-15 buffer with a heavier dampening mechanism up front) and a JP SCS with 85# and 90# springs in this 14.5", carbine length .458.

While I really like the KynShot compared to other hydraulics, I did not feel it was even close to the JP after adjusting spring tensions and slightly adjusting gas in a std carbine length RE. I ended up moving the upper over to a lower with an A5 and A5H4 (6.83oz) installed. That proved to be the ticket as the A5 allows for the same length of travel as does the A2 set up which translates into a longer, smoother recoil impulse.

The least recoil I've ever been able to get was in an 18" .458. I had SBR Ammunition make me a custom pipe with an intermediate length gas system and .972" gas port back in 2011. That was prior to my experimenting with the A5 system and, hence, used an A2 and std weight buffer. That rig barely moved when I shot it, incredibly smooth. Got me a bull Elk at 230yds that year with a hot 350 gr TSX load...

At the end of the day, if I were building another carbine length, 16" big bore, I would absolutely use the A5 and either the A5H3 or A5H4 weight buffers. I'd go STR because 1. it locks and won't move under 'heavier-than-5.56' type recoil; and 2. it's the only adjustable stock that I'm aware of that will fully collapse on an A5 tube and that's generally how I prefer to shoot in any offhand firing position. The cheek weld is, IMO, much better on the STR over the CTR and certainly more beard friendly!

 

[wvlapua]

how about an adjustable gas block to help control the beast as well?

I considered that option, but ultimately it's a hunting rifle and I don't want to screw with adjusting it, besides it's not an over gassed caliber. Not that it wouldn't help.

 

[jasonfaz]

You sir are the man..nice looking rifles. I will take your advice and learn from your experience. Thank you. A5/STR with Slash's 308 springs.

You bet brother. One last thing...if you don't have a std power spring, or something like a SpringCo enhanced power or Wolff XP, it might be prudent to grab one just in case. I use the Slash's spring, but I also shoot 300 grn - 405 grn most often. That heavier spring tension helps A LOT with those heavy, hot loads and when shooting suppressed. With 250s that might be just a hair too much tension, but then again if you're not planning on incorporating an adjustable gas block then you should be golden. Just a thought... Good shooting my man!

 

[wvlapua]

You bet brother. One last thing...if you don't have a std power spring, or something like a SpringCo enhanced power or Wolff XP, it might be prudent to grab one just in case. I use the Slash's spring, but I also shoot 300 grn - 405 grn most often. That heavier spring tension helps A LOT with those heavy, hot loads and when shooting suppressed. With 250s that might be just a hair too much tension, but then again if you're not planning on incorporating an adjustable gas block then you should be golden. Just a thought... Good shooting my man!

Solid info.. You helped spend my money, but definitely saved me even more. Not to mention the hassle and time spent experimenting. Thank you again for the no b.s. answers and for being a valued member of SH.

 

[3GunRunner]

I considered that option, but ultimately it's a hunting rifle and I don't want to screw with adjusting it, besides it's not an over gassed caliber. Not that it wouldn't help.

Gas impingement rifles can all be over gassed regardless of what it is chambered in. If a suppressed is indeed one of the ways the rifle will be run then there isn't really any other way to correctly fix the problem of the additional pressure sent to the operating system. The other issue of adding weight to the buffer is the reciprocating mass (additional felt recoil, push pull feel as the bolt cycles).

I don't see why a hunting rifle operating correctly would be any less important.

 

[wvlapua]

Gas impingement rifles can all be over gassed regardless of what it is chambered in. If a suppressed is indeed one of the ways the rifle will be run then there isn't really any other way to correctly fix the problem of the additional pressure sent to the operating system. The other issue of adding weight to the buffer is the reciprocating mass (additional felt recoil, push pull feel as the bolt cycles).

I don't see why a hunting rifle operating correctly would be any less important.

You have my attention. I have possibly received bad info from a biased source, but was under the impression that adjustable gas blocks are prone to drifting, leaking, and failure. I have no experience whatsoever with them. It's definitely something I'm interested in now and need more user info about. I was under the impression that they are more of a target rifle component and can cause reliability issues, especially with climate changes. I'm here to learn and am fairly new to gas impingement (6 yrs).

 

[3GunRunner]

1. gas leaking - This is typically only a problem with set screw attachment type gas blocks, adjustable or not...
2. gas "tune" self adjusting or losing proper adjustment - Many gas block options have locking devices to prevent the screw or adjuster from being able to move. the newer JP blocks are coming out with a brass locking screw or you could choose a ball-detente version like the Syrac.
3. climate - as long as you leave a decent operating window when setting up the gas block this is not a concern. Just like you could shoot many different weight loads without re-adjusting unless you were hunting for that 'perfect' recoil impulse like in competition setups.

If you have further questions feel free to ask and I will do my best to fill in the info needed.

 

[yoteman]

I tried KynShot's std 308 buffer (same 3.25" length as std ar-15 buffer with a heavier dampening mechanism up front) and a JP SCS with 85# and 90# springs in this 14.5", carbine length .458.

While I really like the KynShot compared to other hydraulics, I did not feel it was even close to the JP after adjusting spring tensions and slightly adjusting gas in a std carbine length RE. I ended up moving the upper over to a lower with an A5 and A5H4 (6.83oz) installed. That proved to be the ticket as the A5 allows for the same length of travel as does the A2 set up which translates into a longer, smoother recoil impulse.

The least recoil I've ever been able to get was in an 18" .458. I had SBR Ammunition make me a custom pipe with an intermediate length gas system and .0972" gas port back in 2011. That was prior to my experimenting with the A5 system and, hence, used an A2 and std weight buffer. That rig barely moved when I shot it, incredibly smooth. Got me a bull Elk at 230yds that year with a hot 350 gr TSX load...

At the end of the day, if I were building another carbine length, 16" big bore, I would absolutely use the A5 and either the A5H3 or A5H4 weight buffers. I'd go STR because 1. it locks and won't move under 'heavier-than-5.56' type recoil; and 2. it's the only adjustable stock that I'm aware of that will fully collapse on an A5 tube and that's generally how I prefer to shoot in any offhand firing position. The cheek weld is, IMO, much better on the STR over the CTR and certainly more beard friendly!

bad A$$
I LIKE BOTH
THANKS FOR THE PICTURE

 

[wvlapua]

Thank you..something else to add to my order. Lol

1. gas leaking - This is typically only a problem with set screw attachment type gas blocks, adjustable or not...
2. gas "tune" self adjusting or losing proper adjustment - Many gas block options have locking devices to prevent the screw or adjuster from being able to move. the newer JP blocks are coming out with a brass locking screw or you could choose a ball-detente version like the Syrac.
3. climate - as long as you leave a decent operating window when setting up the gas block this is not a concern. Just like you could shoot many different weight loads without re-adjusting unless you were hunting for that 'perfect' recoil impulse like in competition setups.

If you have further questions feel free to ask and I will do my best to fill in the info needed.

 

[LRRPF52]

Jasonfaz,

I don't care what anyone says, but I like your style in rifles. Each one is a composition of purpose-selected components, and your finish work tops it off. They aren't just some gun show grade collaboration of parts, sprayed over with Krylon to make them look cool.

There is actually a method to the madness as to what you're selecting for critical parts, furniture, and accessories, based on lots of first-hand experience that focuses not only on reliability, but accuracy and terminal performance.

I'd like to see a line-up of all your projects, as they have a unique feel and presentation to them that sets them apart from what we typically see. Great feedback on the recoil system as well, backed up with your testing with .458 SOCOM. Posts like yours are what I was used to seeing on the Hide more frequently. I wish there were more like it nowadays.

 

[jasonfaz]

Thanks brother. I appreciate that, especially coming from you. While all of the info you can gather from all the experience out there on sites like the Hide is extremely valuable, I think it's tough to apply it without having a lot of experience. Without experience one might just not know what they really want - they might think so - but it's often hypothetical and encompasses so many subjective variables and application-specific nuances that all the recommendations become hard to sort through unless you can relate what someone is suggesting to a situation you've been in or an experience you've had time and time again. I can't count how many times I didn't think something through very thoroughly and ended up proving to myself that I was a dumbass. So I just kept shooting and applied what I learned along the way.

In the case of the 458 for example, which I didn't even start shooting until about 8 years ago, I started with a stock RRA 16" carbine. Last factory gun I ever bought. I've built 7 .458 SOCOMs since then only because I constantly seem to identify a specific area that I feel I can improve upon and genuinely believe that, after making such changes, the rifle will better fit my intended uses. Often what I "want" to change doesn't coincide with a product that actually exists in the form I think it should. I've decided just to figure out how to make it happen myself and start machining away. It takes forever, and has been a significant investment, but I think that's resulted in some pretty unique, accurate, really nice shooting rifles.

Anyway, good to hear some positive feedback on the rigs being churned out over the years!

 

[jwb47]

jason fraz if you dont mind me asking what kind of tube is that on your 18 inch rifle . I have a lite weight yhm on my 458 socom and I really dont need all the rails on it . its like having a hack saw on your hands and shooting bags .

 

[jasonfaz]

It's an Apex Machine Gator Grip handguard. Back then, it was one of only a few options available in the lightweight, modular category. It was nice, but expensive for what it is. I didn't necessarily like the design of the handguard as it relates to where the tubular section meets underneath the top rail. It's too close and makes the barrel appear to be positioned in the lower 1/3 of the handguard as opposed to running down the center of it. Im also not a huge fan of the 2" outside diamter fore ends. I wouldnt actually buy another one over current offerings from Midwest Industries, KMR, URX4 and 10-12 others that also have a tubular, modular design but are also lighter, slimmer and incorporate a better over all design both aestetically and functionally.

 

[wvlapua]

Little update..I have an SLR Sentry 7 clamp on gas block ordered. My A5 components should arrive tomorrow. The STR is sitting in a shopping cart waiting for me to make up my mind on which grip to get. I'm torn between the moe plus and ergo 2.