Does stacked quarters help?

[xagent]

I put six in the tube, couldn't tell a difference.  

[BigBamBoo]

The quarters or shims are to limit over travel of the bolt/buffer. If you do not have excessive bolt travel or are not wanting a short stroke system, then "shimming" to limit bolt travel will not do much.

[StealthyBlagga]

I assume you mean a 9mm AR15? If you have a carbine-length buffer in a carbine length stock, then adding the coins (or other spacer, or longer buffer) will shorten the bolt stroke. The recoil will feel sharper, but the cycle will also be faster, and the gun will shoot flatter and get back on target quicker. You want to allow the bolt to travel back just far enough that the bolt catch will still function, but no further.

[Flatland Shooter]

I installed just enough quarters that the bolt will clear the bolt catch by 1/4".   This was done to reduce the amount of running start the bolt had when it hits the bolt catch.  I'd read that the AR-9 carbines are tough on bolt catches but so far the stack of quarters trick has spared mine.

 

The faster stroke and flatter shooting is just a perk in my case.  This was more noticeable after I switched out the 9mm (.308) recoil spring with a .223 recoil spring. Muzzle movement increased with the lighter spring but it solved a problem I was having with doubling. 

 

Bill

[DFABOVE]

I put in the stacked quarters to limit over travel on my magpul rifle stock equipped PCC and got an extra benefit of better weight/balance distribution.

[1911luvr]

I use just enough quarters to keep my JP SCS29mm from preventing the upper from swinging open. I used to run more (six I think), but I always had to push out the takedown pins to open the upper.


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[Flatland Shooter]

I'm using $1.75 in carbine length buffer tubes (carbine buffer) and $2.25 in rifle length buffer tubes (rifle buffer).  This will get me 1/4" clearance between the bolt and the bolt catch when fully retracted.

 

I don't really see any difference in balance with the coins in place.

[mitommy]

I’m wanting to give this a try. Where do you put the quarters?  
between bolt & buffer?

[Beef15]

2 hours ago, mitommy said:

I’m wanting to give this a try. Where do you put the quarters?  
between bolt & buffer?

Drop them in the empty buffer tube, behind the spring and buffer.

[Jwbfx4]

I didn’t noticed much of a difference when I added 6 quarters. But I did it to allow bolt travel. 

[ltdmstr]

I had problems with empty cases ending up behind the hammer due to excess bolt travel, so I added a 1" piece of aluminum rod with a stainless washer in front of it, then the spring and buffer.  Since I did that, it runs 100%.

[MemphisMechanic]

On 8/27/2017 at 4:34 PM, xagent said:

I put six in the tube, couldn't tell a difference.  

The gun won’t shoot any softer. If anything felt recoil will increase slightly.

 

But, *if* you’ve gotten your buffer weight and recoil spring reasonably well tuned, when you crush the gun back hard against your shoulder like a gorilla and really lean into it? The dot won’t move as much when you’re shooting fast.

 

If your grip, stance, and spring/buffer/ammo tuning isn’t already done... there won’t be much of a difference.

[MoRivera]

For mine it was seven quarters.  Snapped a bolt catch without them.  I had nylon spacers made the same thickness.

[RaylanGivens]

You can short stroke before the bolt catch... 

 

The actual limit is to make sure you leave enough room for the trigger to reset... 

 

Edited April 21, 2020 by RaylanGivens

[zzt]

Right now my PCC with 5.5" barrel, held as RG suggests is perfectly balanced for 147gr @ 985fps loads.  That is 144FP.  My goal, if they ever open up the clubs again, is to try out the new stuff I bought in an effort to get it balanced for the 124gr 139PF load I shoot in my Open gun.  That way I will only have to make one load for SCSA.

 

With 124gr ammo I tried removing the 3 oz. weight from the bolt.  Too violent.  I put the weight back in and tried short stroking using Blitzkrieg's 3/4" spacer.  It did nothing.  I think it was because the spring stacked at the end of the stroke and the muzzle rose.  So I ordered a Tubb flat wire 5.56 carbine spring.  That will not stack even when short stroked.  While waiting I read all of maxamundo's posts on buffers, springs, etc.  So I ordered the 25 lb. wave spring he used.  I'll put a quarter between it and the Tubb spring until I can get the plastic buffer spring cap.  My goal is to short stroke the gun so the buffer never actually bottoms out and raises the muzzle.

[BartCarter]

On 4/21/2020 at 5:58 AM, zzt said:

...While waiting I read all of maxamundo's posts on buffers, springs, etc.  So I ordered the 25 lb. wave spring he used....

I don't believer  he  uses wave springs any longer.

[zzt]

3 hours ago, BartCarter said:

I don't believer  he  uses wave springs any longer.

 

That's okay.  I ordered some and they will be here on the 6th.  I'll try them for no other reason that I like to experiment and learn.  They are bound to feel different than the Blitzkrieg Short-Stroke spacer.

[TRUBL]

SO what you do not undestand about wave springs is that you need to limit the travel of said springs.....if not, they go flat and break. wave springs, the way they are used in buffer tubes is not they way they were designed to be used, all you are doing by running them in series is increasing preload and overall power of your set up, you'd be better served buying a strong spring. Now, if the secondary spring is seperated, like in the case of MBX, TACCOM or ARMASPEC, that is a true cushion, I only wish that Armaspec would have used a stronger secondary spring.

[zzt]

I will be running a Tubbs 5.56 flat wire spring with a Blitzkrieg buffer.  It does not coil bind.  The wave spring is an attempt to short stroke with a softer effect than the Blitzkrieg 3/4" steel spacer.  The springs will be separated.  I'll try a quarter first, then the .100", 200", 300" spacers of the MBX short stroke kit.  I may cut down tone of the longer inserts, or I may use it in place of the wave spring.  Since the Tubb does not coil bind even when short stroked, I don't see how the wave would flatten.

 

Doesn't all short stroking increase preload?

[TRUBL]

3 hours ago, zzt said:

 

 

Doesn't all short stroking increase preload?

No sir......quaters will, but a spacer with a head the size of a quarter that can go inside the spring will not

[zzt]

57 minutes ago, TRUBL said:

No sir......quaters will, but a spacer with a head the size of a quarter that can go inside the spring will not

 

I don't see why.  The 'head' that sticks out behind the spring is effectively a stack of quarters.  It may only be .300", but it is something.  

Edited April 28, 2020 by zzt

[MoRivera]

[TRUBL]

2 minutes ago, zzt said:

 

I don't see why.  The 'head' that sticks out behind the spring is effectively short stroking the gun.  It may only be .300", but it is something.  There are several I've seen that are larger than that.

Not ours......the head is only .1" thick.....while the overall length is .5 to .75" long.....do we pre-load? if .1" is preload then yes, but we short stroke up to .75".....if you stack 3/4" of quarters, then you are preloading the spring 3/4"

[TRUBL]

1 minute ago, MoRivera said:

VERY similar to this.......short strokes and very minimal preload, nothing that you would notice

[zzt]

Bummer.  I looked for something like that on your site and didn't find it.  So I ordered the MBX.  I figured I'd cut the length of one of them down to shorten.  I'll search on yours again.

 

Added later.  SO I did search again and did not find it on your web site.  Please send a link.

Edited April 28, 2020 by zzt