View Full Version : Shim Kit / Peel Washer Recommendation - BCM LW Barrels
Hello,
I just picked up my new Saker 762 today. My host has an 11.5" BCM light weight barrel. http://www.bravocompanyusa.com/BCM-Standard-11-5-Carbine-Barrel-light-weight-p/bcm-brl-s-11lw%20std.htm
I didn't think about it when I bought the barrel, but the shoulder area must be .625" OD like the gas block journal. Does anybody make a shim kit or peel washer than is .625" OD? The .75" OD don't seem appropriate.
http://i.imgur.com/OhuXQmYh.jpg (http://imgur.com/OhuXQmY)
http://i.imgur.com/LFVw8nwh.jpg (http://imgur.com/LFVw8nw)
http://i.imgur.com/FQFKzsjh.jpg (http://imgur.com/FQFKzsj)
Look at this system. http://precisionarmament.com/product/accu-washer-system/ The ground washers are 3/4" OD but much thicker than typical shims.
Look at this system. http://precisionarmament.com/product/accu-washer-system/ The ground washers are 3/4" OD but much thicker than typical shims.
Those look nice. Thanks for the suggestion.
The only downside is the cost if you are only doing one barrel. I can scan and send you the instructions if it helps with your decision.
The only downside is the cost if you are only doing one barrel. I can scan and send you the instructions if it helps with your decision.
Don't go through the trouble to scan, but thanks for the offer. I will most likely go with these unless I find a better solution. I don't mind paying $25 for shims when you consider the cost of the suppressor and host.
I used the Precision Armament set, fan-****ing-tastic stuff
BufordTJustice
04-25-15, 23:50
Look at this system. http://precisionarmament.com/product/accu-washer-system/ The ground washers are 3/4" OD but much thicker than typical shims.
These are all I use now, regardless of muzzle device.
I'm so glad that the days of Peel Washers are behind us. I'll have to check out a set of the precisionarmament.com washers.
BufordTJustice
04-26-15, 11:22
I'm so glad that the days of Peel Washers are behind us. I'll have to check out a set of the precisionarmament.com washers.
Oh gawd! How many minutes of my life have I already donated to peel washers? I'm never going back.
AAC has some shims as well, but I haven't used them.
Even better, I'm glad the days of the crush washer are over
AAC has some shims as well, but I haven't used them.
Pappabear runs a lot of their mounts, so I've ended up with a bunch of their shim kits from installing his. They're pretty good.
Sounds like the Accu-Washers are the bee's knees. I just placed my order.
ScatmanCrothers
04-26-15, 15:40
Sounds like the Accu-Washers are the bee's knees. I just placed my order.
They're awesome. I'm still using ones from the first set I bought and I've done 5 rifles so far. They are just the right firmness but soft enough to allow around 3 consecutively sized washers to be considered usable for one muzzle device so if the ideal size you need for a specific mount has already been used you can find one that's close enough to work most of the time.
Plus the set lets you fine tune your installation for timed devices. A smaller sized washer with minimal torque required to time a suppressor mount used with Rocksett or a slightly larger washer to be able to crank down on for whatever reason. Well worth the price IYAM.
They're awesome. I'm still using ones from the first set I bought and I've done 5 rifles so far. They are just the right firmness but soft enough to allow around 3 consecutively sized washers to be considered usable for one muzzle device so if the ideal size you need for a specific mount has already been used you can find one that's close enough to work most of the time.
Plus the set lets you fine tune your installation for timed devices. A smaller sized washer with minimal torque required to time a suppressor mount used with Rocksett or a slightly larger washer to be able to crank down on for whatever reason. Well worth the price IYAM.
The washers are NOT the least bit soft!!! You will wring off the threads on your barrel before compressing them! Using your logic one would just smear some rockset on it and hand tighten to time the MD. Read the instructions.
So their different thickness then?
BufordTJustice
04-26-15, 17:18
So their different thickness then?
Yes, but they are all relatively very thick compared to other shim sets.
Yes, but they are all relatively very thick compared to other shim sets.
For the record the thinnest one is twice as thick as the largest AAC shim. Preaching to the choir to you but think of it a system not shims.
BufordTJustice
04-26-15, 20:41
For the record the thinnest one is twice as thick as the largest AAC shim. Preaching to the choir to you but think of it a system not shims.
Roger that and thank you for the info.
ScatmanCrothers
04-26-15, 22:53
The washers are NOT the least bit soft!!! You will wring off the threads on your barrel before compressing them! Using your logic one would just smear some rockset on it and hand tighten to time the MD. Read the instructions.
What are you talking about? You read "just the right firmness but soft enough..." as "they're soft"? Cause that's not how that works.
Regardless, these washers do compress. We're not talking crush washer here but there is enough softness [dont read: soft] to allow for varying degrees of torque. Try putting one on, torquing your MD down, and then removing it. You'll notice that it's been compressed and that it is no longer the same thickness as before and you didn't even have to wring off your barrel threads. That's why the instructions you suggest I read advise that the MD will rotate an additional 10-30 degrees after reaching hand tightened.
But yet using "my logic" the answer is to smear rocksett on there and hand tighten to time the MD? I'm not even sure how you got to that conclusion or what the point of your comment was honestly.
I dont really want to get in the middle of this spat, but I would like to add a couple comments about the terms "soft" and "compressible". What we are really talking about is deformation. Do the washers deform when the muzzle device is tightened down? Absolutely. Elastic materials will deform under stress. They can either deform elastically or plastically.
I think the question we should be asking is what type of deformation is occuring. Elastic deformation is when you stress a material, it deforms, and comes back to its original shap when unloaded. A spring working in its intended range is a good example of this. Now take that spring and streatch it out beyond where it is intended. It will be permanantly deformed because you have exceeded the elastic limit and have plastically deformed the material. A crush washer is another good example of plastic deformation.
Edit to add: It seems to me that these washers are intended to work in the elastic range of the material, but I do not have experience with them yet.
ScatmanCrothers
04-27-15, 06:50
I dont really want to get in the middle of this spat, but I would like to add a couple comments about the terms "soft" and "compressible". What we are really talking about is deformation. Do the washers deform when the muzzle device is tightened down? Absolutely. Elastic materials will deform under stress. They can either deform elastically or plastically.
I think the question we should be asking is what type of deformation is occuring. Elastic deformation is when you stress a material, it deforms, and comes back to its original shap when unloaded. A spring working in its intended range is a good example of this. Now take that spring and streatch it out beyond where it is intended. It will be permanantly deformed because you have exceeded the elastic limit and have plastically deformed the material. A crush washer is another good example of plastic deformation.
Edit to add: It seems to me that these washers are intended to work in the elastic range of the material, but I do not have experience with them yet.
They permanently deform. Once you've used one it's no longer to act like it originally did in the instruction's selection process.
That shim kit from Precision Armament works well. Usually you can get a couple barrels out of one kit as well, I think I've done as many as 3 on one kit.
I'm willing to bet that the precision shims are deforming to the shape of some of the annoying shoulder shapes on many barrels. That transition from the shoulder, between the threads often has a radius to it that flanges shims/washers.
I'm willing to bet that the precision shims are deforming to the shape of some of the annoying shoulder shapes on many barrels. That transition from the shoulder, between the threads often has a radius to it that flanges shims/washers.
Mark, I don't think they are deforming at all when torqued to the normal 20-30 FP. Some guys will never take their foot out of their mouth no matter how overwhelming the proof is that they are wrong.
Possibly... I've never tried the precision kit.. But I've seen my thin AAC shims deform. Those are MUCH thinner than anything pictured in the precision kit.
I always put the thickest shim on the barrel end , I have only used AAC shims but have had zero problems. like the color coding= thickness helps getting the final adjustment
ScatmanCrothers
04-27-15, 22:57
Mark, I don't think they are deforming at all when torqued to the normal 20-30 FP. Some guys will never take their foot out of their mouth no matter how overwhelming the proof is that they are wrong.
Man, you have really taken issue with this huh? Let me take my foot out of my mouth so that my endorsement for this excellent product that you also like doesn't rub you in such a wrong way. Or so someone can let me know where my understanding went wrong. The instructions advise that once you've selected the correct washer based on their provided chart to note that an additional 10-30 degrees of rotation is possible depending on the final tightening torque. Is it safe to assume that Precision Armament means 10-30 degrees of additional rotation that falls within recommended torque settings for a muzzle device on this platform? Surely they don't mention a 30 degree possibility that would require excessive force would they? I wouldn't think so. And why start at 10 and not 1? Minimal torque requirement, no?
Now seeing that each washer is in a 20 degree increment is it not correct to think that any of multiple consecutive sized washers would have the ability to work for a given muzzle device with up to 30 degrees of spin available when torquing? That's been my experience. Is that incorrect? They also note in the instructions that applying grease to the washer and threads will reduce friction and allow for further spinning for a particular torque load. They aren't recommending excessive torque values again are they?
On my first install I chose a washer that was too large to time the device correctly so I removed it because it came up short. When I started hand tightening the sizes around it I tried that particular used size again and it timed differently with hand tightening. Nothing drastic, but it had been permanently deformed and was now smaller. It was just an observation. I wouldn't be able to correctly use that size in conjunction with the graph. It is what it is. I don't know if it was because of the barrel, because of the washer, or a case of a sudden Herculean effort on my part with a torque wrench but it definitely deformed.
I also said that it was nice to be able to pick a washer to use minimal torque with rocksett for a suppressor mount. Again, minimal torque setting as in within the range of acceptable torque values for a MD on this platform. You decided to interpret that as slather on the rocksett with some hand tightening and off you go. That's not what I said and I thought the acceptable torque value thing would be understood in a discussion like this. Clearly I was wrong. I prefer to stay on the lower side of acceptable torque values myself and this set is great for letting you get that timing nice and close with hand tightening before torquing. Any issues here?
TL/DR, I know. Just genuinely interested in why you're so chapped by my first hand account comments.
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