Increase my buffer weight?

[Iamero]

I've heard that increasing your buffer weight can help keep the bolt from unlocking so fast and swiping the brass on an AR308 style platform.

I have a DPMS LR308 with the 20" barrel and got it threaded for a suppressor. The factory DPMS buffer is 5.87oz and I was wondering if something like a 6.5oz would help or what other solutions there are to bolt swipe.

This is a mild handload, and it even swipes on factory 150gr PMC. Small swipes don't hurt my feelings too much, but the burrs are annoying and it sometimes even bends the case head a little bit (even on a min load I tested).

Suggestions? Where to buy a heavy rifle length buffer?

 

[kingzero]

It certainly helped me. An adjustable gas block is a must if you don't already have one. I went with all tungsten weights in my rifle length buffer with a suppressed 20" barrel and it ran great. It was around 10 oz if I remember. Of course you can mix and match weights.

This is the best source I found for tungsten.

https://www.kakindustry.com/ar-15-p...ndividual-buffer-parts/buffer-weight-tungsten

 

[Iamero]

Yea I have the adjustable block and need to turn it down even more. I have the set screw about half way in but it still cycles on every load (both 150 and 175). JP says you need to use a tap to thread the hole on the gas tube, so I am waiting for that to come in to be able to do that.

How do those buffer weights attach? Will they work with my factory DPMS buffer? I've never used additional weight before.

 

[bfoosh006]

KAK also sells a complete 9.3oz Heavy weight .308 rifle buffer...

Also consider a Tubbs Flatwire .308 spring... it has more spring weight on the closed BCG, right where you want it to help "retard" the extraction by those few milliseconds.

I use both the Tubbs and 9.3oz, those ....along with the adjustable gas block.... dramatically cut down on the brass being abused by my .308 middie.

Those parts also make for a MUCH softer shooting firearm... I can watch the bullet impacts on target and can fire follow up shoots much faster.

Here are some spring weight measurements from David Tubbs... just food for thought.

A2 (old) - 7.6lb closed, 14.5lb open
A2 (new) - 9.1lb closed, 16.7lb open
Tubb Flatwire - 10.5lb closed, 16.3lb open
Tubb .308 Flatwire - 13lb closed, 16.7lb open
SpringCo White ? (standard) - 8.3lb closed, 16.3lb open
SpringCo Red (extra) - 10.5lb closed, 18.4lb open
SpringCo Orange (increased) - 13.9lb closed, 24.8lb open


IMHO, an extra power spring isn't needed , nor wanted.

I tried both the "Red" and "Orange" ... both caused needless muzzle dip, and were slamming the BCG really hard into the breach face

 

[kingzero]

Yea I have the adjustable block and need to turn it down even more. I have the set screw about half way in but it still cycles on every load (both 150 and 175). JP says you need to use a tap to thread the hole on the gas tube, so I am waiting for that to come in to be able to do that.

How do those buffer weights attach? Will they work with my factory DPMS buffer? I've never used additional weight before.

You replace the existing weights with the tungsten ones. There is a roll pin in the back of the buffer that holds the bumper on, and weights in. Just drift that pin out, remove the bumper and dump out the weights. There should be rubber discs between each weight, be sure to put them back in with the new tungsten. Reinstall bumper and pin and rock on.

 

[Iamero]

Sweet thanks!

 

[Iamero]

They don't have much of a description on their website so I was just wondering if order 1 of these is enough or what I need to do:

https://www.kakindustry.com/review/product/list/id/503/category/124/

 

[NukeMMC]

I bought a set of 3 weights from ebay:
http://www.ebay.com/itm/262957493728
Fit and finish is great. I haven't shot my GAP10 with the buffer re-weighted yet but will as soon as I get back next week.

 

[Iamero]

Thanks Nuke, just ordered a set. Would you change the spring too or is my factory DPMS fine?

 

[NukeMMC]

Both my 308 ar10 and my GAP10 came with Tubb flat wires, so I cannot be a good advisor on that. I do know that the GAP10 had all-steel weights in the buffer and the AR10 had all-steel but 1 aluminum (????). When I get home next week I plan to do some weighing of buffers and shooting with different weights. Both rifles are TOUGH on brass with the can on. The AR10 leaves some pretty heavy burrs on the M118LR. The GAP10 leaves burrs about 1/2 the time.

 

[NukeMMC]

Apparently heavybuffers.com is pretty into this subject. Personally, I want to be able to tune my rifles to the loads I work up for them.

 

[bfoosh006]

Apparently heavybuffers.com is pretty into this subject. Personally, I want to be able to tune my rifles to the loads I work up for them.

Find out if it is a solid piece... IE no moving internal weights.( Dead blow effect )

I don't like solid buffers.... they will cause your BCG to smack the breach face... like a steel hammer on an anvil will bounce... the buffers with moving weights ( conventional ) smack more like a dead blow hammer....with more of a thud and very little bounce.... That is part of why Uncle Sugar uses the ones they do now.

Some of the other products say "Machined from solid 303 Stainless Steel with Tungsten anti-bounce internal weights.".... the .308 rifle doesn't mention it... so it might be like their Vltor A5's that say...."We machine these from solid 303 Stainless Steel and include a Stainless Steel roll pin for a lifetime of trouble-free performance."

Just sayin'.

 

[Smokyred]

Find out if it is a solid piece... IE no moving internal weights.( Dead blow effect )

I don't like solid buffers.... they will cause your BCG to smack the breach face... like a steel hammer on an anvil will bounce... the buffers with moving weights ( conventional ) smack more like a dead blow hammer....with more of a thud and very little bounce.... That is part of why Uncle Sugar uses the ones they do now.

Some of the other products say "Machined from solid 303 Stainless Steel with Tungsten anti-bounce internal weights.".... the .308 rifle doesn't mention it... so it might be like their Vltor A5's that say...."We machine these from solid 303 Stainless Steel and include a Stainless Steel roll pin for a lifetime of trouble-free performance."

Just sayin'.

^That is a good piece of information.

Dave

 

[Iamero]

I bought the tungsten buffer weights and installed them today. Don't have a scale to tell me exact buffer weight now but I've heard it puts it right around 10oz. Going to load up some more rounds today and report back on how it changed (or didn't) the bolt swipes.

 

[bfoosh006]

From KAK's webpage for the configurable carbine buffer... so you will need to do some math.... YMMV

IE... tungsten = 1.86666oz / weight... Steel + 1oz.... Aluminum = .5666666oz + your buffer tube and disc's and bumper weight.



CONFIGURE AND TUNE YOUR BUFFER FOR YOU SPECIFIC NEEDS

USING DIFFERENT COMBINATIONS OF THE SUPPLIED PARTS

A = ALUM

S= STEEL

T = TUNGSTEN

A	A	A	1.7	OZ
S	A	A	2.2	OZ
A	S	S	2.6	OZ
S	S	S	3.0	OZ
T	A	A	3.0	OZ
T	S	S	3.8	OZ
A	T	T	4.3	OZ
S	T	T	4.7	OZ
T	T	T	5.6	OZ

 

[Iamero]

I'm guessing the factory ones were aluminum because they were really light weight. I replaced 3/5 of the aluminum ones with the supplied tungsten ones and ran it over the weekend. I threw in surplus German ammo and ran through 8 rounds flawlessly. No bolt swipes on the first 6, very minor ones on the last 2 but it was mostly where it wiped away the grime on the case head. Those are lighter weight rounds (I believe 147gr) so I will be curious to try it on some of my 175gr hand loads since those were the ones with the hard swipes previously.

By the way, I chronoed my loads at avg. fps of 2660 so that's about right in line with what others stated out of factory ammo and 20" barrrels. I think I am going to stick with this load unless the bolt swipes are still present in which case I will load it down to 2580-2600 and call it good.

Thanks for the chart above, that's helpful!

 

[NukeMMC]

I just got done weighing things out on my GAP10 and AR10. The buffer with roll pin, rubber cap and the rubber wads weighed 654gn, or 1.5oz. Each steel weight is 280gn, or .6oz and each of the Tungsten weights are 638gn, or 1.5oz. By changing 4 of the 6 weights from steel to tungsten, the GAP10 buffer is now 8.6oz. The AR10 I swapped to 3 steel and 3 tungsten (total of 7.8oz). I will be getting to the range later this week or this weekend to check results.

 

[Iamero]

Let me know what you come up with. I haven't had a chance to fire my hand loads again yet, so hopefully I will do that again here when it isn't 95 out with 80%+ humidity. That just sucks to shoot in.

 

[NukeMMC]

Had the GAP10 and AR10 out yesterday. The buffer weights seem to be working as the brass shows SIGNIFICANTLY less raised metal with most showing just ejector swipes. I'll get some before/after pics together but to summarize ... I just ordered some more Tungsten weights

 

[FatBoy]

Nuke,

was this with the 260s and AEM30?

Chris

 

[NukeMMC]

Nuke,

was this with the 260s and AEM30?

Chris

Yes and no. This is a GAP10 in 260, but I have an Ops Inc 3rd Model .30cal can. It's 2" longer behind the muzzle than the AE30.
I use the same can on my .260 bolt rifle, AR10 in .308 and my new 300WM.

 

[bfoosh006]

Very nice... glad to see added buffer weights helped.

 

[Iamero]

Nuke,

I'm curious to whether or not adding too much weight would cause excessive momentum on forward stroke? Or is that force more dependent on the spring tension vs the buffer weight.

 

[FatBoy]

Yes and no. This is a GAP10 in 260, but I have an Ops Inc 3rd Model .30cal can. It's 2" longer behind the muzzle than the AE30.
I use the same can on my .260 bolt rifle, AR10 in .308 and my new 300WM.

so are you satisfies that the brass damage you were getting on the AR is fixed or is there still some tweaking to do? I recall you didn't have an issue w/o the can on but it swiped badly with the can.

 

[NukeMMC]

We still have some tweaking to do. It's still making some slight swiping in the GAP10 but there were still a few with raised metal, though certainly not to the extent as before and there was a little bit of raised metal on most of the M118LR and 175FGMM in the AR10.
Yes. When running without the can, the brass just had light swipes in both rifles.

 

[NukeMMC]

Nuke,

I'm curious to whether or not adding too much weight would cause excessive momentum on forward stroke? Or is that force more dependent on the spring tension vs the buffer weight.

I have heard, though I do not remember where from, that excessive weight in the carrier or buffer has had problems for some people breaking or at least cracking the bolt catch. Whether this is a function of the spring or the weight itself or a combination thereof I am not 100% sure. I do know that momentum is a function of mass and velocity so I am sure that either could affect bolt catch life. Which one will be the predominant effector is a big question.

 

[WYO09]

KAK also sells a complete 9.3oz Heavy weight .308 rifle buffer...

Also consider a Tubbs Flatwire .308 spring... it has more spring weight on the closed BCG, right where you want it to help "retard" the extraction by those few milliseconds.

I use both the Tubbs and 9.3oz, those ....along with the adjustable gas block.... dramatically cut down on the brass being abused by my .308 middie.

Those parts also make for a MUCH softer shooting firearm... I can watch the bullet impacts on target and can fire follow up shoots much faster.

Here are some spring weight measurements from David Tubbs... just food for thought.

A2 (old) - 7.6lb closed, 14.5lb open
A2 (new) - 9.1lb closed, 16.7lb open
Tubb Flatwire - 10.5lb closed, 16.3lb open
Tubb .308 Flatwire - 13lb closed, 16.7lb open
SpringCo White ? (standard) - 8.3lb closed, 16.3lb open
SpringCo Red (extra) - 10.5lb closed, 18.4lb open
SpringCo Orange (increased) - 13.9lb closed, 24.8lb open


IMHO, an extra power spring isn't needed , nor wanted.

I tried both the "Red" and "Orange" ... both caused needless muzzle dip, and were slamming the BCG really hard into the breach face

I don't mean to high jack this thread but I've been trying different combinations of buffer springs and weights to try to remedy my weak ejection on my 6.5 creedmoor DPMS style gas gun. Currently I'm running a Tubbs Flat Wire with a standard buffer. The weak ejection didn't start until I changed my bolt from the standard Aero bolt to the JP HP Enhanced Bolt as well as adding a Sun Devil adjustable gas key to the BCG. I've tried the JP SCS Heavy version with the same result. I'm wondering if there needs to be more weight than the JP Heavy SCS can provide and if by adding more tungsten to the standard buffer it would help? Before I added the adjustable gas key and JP HP Bolt the brass was ejecting strong but at 1 o'clock so now I'm trying to get things tuned just right and was wondering what others have experienced if any with this. Thank you.

 

[bfoosh006]

I have heard, though I do not remember where from, that excessive weight in the carrier or buffer has had problems for some people breaking or at least cracking the bolt catch. Whether this is a function of the spring or the weight itself or a combination thereof I am not 100% sure. I do know that momentum is a function of mass and velocity so I am sure that either could affect bolt catch life. Which one will be the predominant effector is a big question.

Actually... that is a bolt over-travel issue most likely... if the BCG is allowed to much "space" between the bolt catch and the bolt face... it can smack ( your momentum comment kind of applies here ) the bolt catch hard enough to break them... It is a pretty common thing in 9MM Colt pattern AR's.

A common "fix" is added Quarters to the bottom of the buffer tube ( as spacers ) to adjust / limit the amount of travel of the BCG into the buffer tube, and as a result minimizing the "space between the bolt face and bolt catch. Ideally you'd like about 3/16 of an inch between the bolt face and bolt catch.

Limiting that over-travel helps keep the "momentum" from hitting the bolt catch with to much energy.

 

[bfoosh006]

Nuke,

I'm curious to whether or not adding too much weight would cause excessive momentum on forward stroke? Or is that force more dependent on the spring tension vs the buffer weight.

IMHO, that is more dependent on the spring tension... that is why I don't recommend the Springco Orange and Red springs... those send the BCG and buffer forward hard enough that you se muzzle dip and have basically just moved the recoil problem to out front.

My .308 AR , rifle length stock runs perfect with a 9.3oz rifle length .308 buffer, the OEM BCG, and the Tubbs .308... no muzzle dip, and stays on target easily.

 

[bfoosh006]

I don't mean to high jack this thread but I've been trying different combinations of buffer springs and weights to try to remedy my weak ejection on my 6.5 creedmoor DPMS style gas gun. Currently I'm running a Tubbs Flat Wire with a standard buffer. The weak ejection didn't start until I changed my bolt from the standard Aero bolt to the JP HP Enhanced Bolt as well as adding a Sun Devil adjustable gas key to the BCG. I've tried the JP SCS Heavy version with the same result. I'm wondering if there needs to be more weight than the JP Heavy SCS can provide and if by adding more tungsten to the standard buffer it would help? Before I added the adjustable gas key and JP HP Bolt the brass was ejecting strong but at 1 o'clock so now I'm trying to get things tuned just right and was wondering what others have experienced if any with this. Thank you.

IMHO... your adjustable gas key needs to be tuned to allow more gas. Adding more weight will only weaken your ejection more.

Also how many rounds with the JP HP bolt ? ... In other words, does it need to be allowed to "break in" more. ( a normal thing )

 

[WYO09]

The JP Bolt has 60 rounds through it, just tinkering with the adjustments. I adjusted the gas so the bolt locks back every time on last round and with single feeds, but I'll try to turn it up some. I was unaware of the bolt break in period I guess i'll its back to the range and more adjusting. Thank you for the info.