View Full Version : YHM BUIS QUESTION
Gents,
I have questions concerning some sights that were made by YHM. These sights were sold to Bushmaster and were part of the package that my employer purchased.
1. Anyone have experience with these particular sights?
2. I have had several of them (about 1 in 10) that would not allow the front sight post to adjust correctly. The front sight post would make about 5 revolutions and stop even though it was not bottomed out.
3. Since there is no elevation adjustment provision at what distance were these meant to be used?
4. What benefit would have been gained from making them out of aluminum? They actually cost more than a steel BUIS and they damage easily.
I have both the flip-up front and rear sights on my gun. I had the same problem with the front sight not turning down far enough to get a proper sighting in at 100 yards (using a bullet) until I bought a sight tool that has two sides for the old and new sights. It was a pain at first but the front sight did turn down and I was able to get the correct sight alignment. Good luck, I hope this helps.
"Survival means acting first, Hesitation equals death"
jwork,
I actually have sight tools and they don't help. As a matter of fact because these are aluminum I will not allow personnel to use anything else because they are so easily scored up and then the sight won't move.
Some of the sights will actually go all the way down and sone will not. I had a couple of the other knowledgeable guys look at them and we think it may be the hole is not threaded all the way or the hole is not deep enough. I have been cutting about 1/8" off the post and that seem to be working.
BTW- I emailed YHM about this the same day and have yet to hear from them. I even attached photos. My previous responses from them were less than stellar.
I have both the flip-up front and rear sights on my gun. I had the same problem with the front sight not turning down far enough to get a proper sighting in at 100 yards (using a bullet) until I bought a sight tool that has two sides for the old and new sights. It was a pain at first but the front sight did turn down and I was able to get the correct sight alignment. Good luck, I hope this helps.
"Survival means acting first, Hesitation equals death"
One other idea is you may try taking the sight post out and cleaning out the hole with compressed air or chasing the threads with a tap. Some metal from the cutting of the threads may be in the bottom, Just an idea.
"Survival means acting first, Hesitation equals death"
jwork,
Actually tried that before everything else and it was a NO GO.
One other idea is you may try taking the sight post out and cleaning out the hole with compressed air or chasing the threads with a tap. Some metal from the cutting of the threads may be in the bottom, Just an idea.
"Survival means acting first, Hesitation equals death"
I was actually going to suggest that. The Company they use for plating packs those holes in sand and they then are packed in oil before they are shipped back to YHM, so they sand tends to get stuck in there very easily.
Let me know what YHM does to remedy this problem, I am kinda curious at what they have to say
-DM-
Still no response and the last (previous) email that I had received stated that the sights were made for BM exclusively, installed by BM and marketed on certain carbines. I told them that was outstanding, but the sights were still manufactured by YHM and not Bushamster.
I was actually going to suggest that. The Company they use for plating packs those holes in sand and they then are packed in oil before they are shipped back to YHM, so they sand tends to get stuck in there very easily.
Let me know what YHM does to remedy this problem, I am kinda curious at what they have to say
-DM-
Still no response and the last (previous) email that I had received stated that the sights were made for BM exclusively, installed by BM and marketed on certain carbines. I told them that was outstanding, but the sights were still manufactured by YHM and not Bushamster.
You will not get anything from them till Monday at the earliest. They are not open on the weekends.
I know of this issue popping up before but as mentioned before it was cured by clowing the excess sand and debris out of the post hole.
Correct as you said these parts are exclusive BM only. BM does the marketing but YHM is the sole manufacturer of them. I personally think they are cheap and useless garbage that I wouldnt even put on an airsoft gun.
If you can get a tap try and tap the threads, maybe the electro plating caused the threads to clog up. Also another idea that just popped into my head take a light and see if there isnt any stubborn packed in sand from when they were at plating.
Again let me know what turns out
-DM-
Manley,
Actually I emailed them on 3 July, yeah I know everyone is on holiday routine. The previous responses I got in May were everything from "we have never had any other complaints" to "we have a different model that you may want to try, etc...". I have thoroughly checked the holes and even had some other armorers here in the AO take a look as well. They are in the opinion that they were not threaded down deep enough or the hole is not deep enough. Unfortunately, I cannot go through and try and tap the threads as there are 500 of these in my inventory and I am a one man show.
I agree about them being cheap pieces of crap and had I been around when this package was purchased I would have done everything in my power to stop it. If I told you how much BM made us pay for the replacement to fix the ones that were damaged or missing you would probably get sick.
You will not get anything from them till Monday at the earliest. They are not open on the weekends.
I know of this issue popping up before but as mentioned before it was cured by clowing the excess sand and debris out of the post hole.
Correct as you said these parts are exclusive BM only. BM does the marketing but YHM is the sole manufacturer of them. I personally think they are cheap and useless garbage that I wouldnt even put on an airsoft gun.
If you can get a tap try and tap the threads, maybe the electro plating caused the threads to clog up. Also another idea that just popped into my head take a light and see if there isnt any stubborn packed in sand from when they were at plating.
Again let me know what turns out
-DM-
Manley,
Actually I emailed them on 3 July, yeah I know everyone is on holiday routine. The previous responses I got in May were everything from "we have never had any other complaints" to "we have a different model that you may want to try, etc...". I have thoroughly checked the holes and even had some other armorers here in the AO take a look as well. They are in the opinion that they were not threaded down deep enough or the hole is not deep enough. Unfortunately, I cannot go through and try and tap the threads as there are 500 of these in my inventory and I am a one man show.
I agree about them being cheap pieces of crap and had I been around when this package was purchased I would have done everything in my power to stop it. If I told you how much BM made us pay for the replacement to fix the ones that were damaged or missing you would probably get sick.
How many of them are all like that, most or all? How many of them are issued?
I sent you a PM with some more info. Let me know how that works out for you.
-DM-
Here's something to consider that might be related, or could be completely off-base. We've seen a lot of YHM folding sights cross the bench. There was a similar complaint about the sight being too tall and couldn't be zeroed. After examining several of these, we found that the one with the complaint was for mounting on a gas block instead of the rail, therefore had a different overall height and similarly effected the post height. Once we realized it, it was clearly obvious. However, they do look similar at first glance. Just something to consider and I hope you get yours' resolved.
Well I had a nice long talk the other day with someone over at YHM. They advised me that the sights are actually installed at Bushamster using their front sight posts. So I believe that what has happened is typical Bushamster quality control put the wrong size posts in them which is what is causing the problem.
Here's something to consider that might be related, or could be completely off-base. We've seen a lot of YHM folding sights cross the bench. There was a similar complaint about the sight being too tall and couldn't be zeroed. After examining several of these, we found that the one with the complaint was for mounting on a gas block instead of the rail, therefore had a different overall height and similarly effected the post height. Once we realized it, it was clearly obvious. However, they do look similar at first glance. Just something to consider and I hope you get yours' resolved.
Well I had a nice long talk the other day with someone over at YHM. They advised me that the sights are actually installed at Bushamster using their front sight posts. So I believe that what has happened is typical Bushamster quality control put the wrong size posts in them which is what is causing the problem.
all because front sight post.damn!!!have you been able to fix the problem swapping it or still NO-GO?I have always disliked the flip sights this seems to give me more reason to go with the standard front sight.please keep us posted this had me scratching my head
Be safe PFC Bowers
Warpig,
Don't get me wrong. YHM has some good sights and flip sights are good. These particular ones are just crap and they don't belong on anything but airsoft. What I have been doing is cutting about 1/8 in. off the bottom and it seems to be good. Unfortunately. buying new sight posts for 500 carbines is rather cost prohibitive. How's your project and reclass going?
all because front sight post.damn!!!have you been able to fix the problem swapping it or still NO-GO?I have always disliked the flip sights this seems to give me more reason to go with the standard front sight.please keep us posted this had me scratching my head
Be safe PFC Bowers
Don't get me wrong. YHM has some good sights and flip sights are good. These particular ones are just crap and they don't belong on anything but airsoft. What I have been doing is cutting about 1/8 in. off the bottom and it seems to be good. Unfortunately. buying new sight posts for 500 carbines is rather cost prohibitive.
Was it these sights, by chance?
http://i76.photobucket.com/albums/j18/Skintop911/August%20Bushmaster/IMG_4370.jpg
Warpig,
Don't get me wrong. YHM has some good sights and flip sights are good. These particular ones are just crap and they don't belong on anything but airsoft. What I have been doing is cutting about 1/8 in. off the bottom and it seems to be good. Unfortunately. buying new sight posts for 500 carbines is rather cost prohibitive. How's your project and reclass going?cost is a factor for 500 Good god thats some cash.My project is good ordered the upper vise block you showed me just waiting now:( .Reclass is set for Fort Leonard Wood in a couple months.Ft Lost in the woods.I was on their site ad noticed some of the trainingis for MK-19 ,and 249 and 240.I already had training on those during my 19 Kilo training at Ft Knox.I can't wait to get my hands on the MK-19 again it makes me warm and fuzzy inside:D Ooopps Back to the thread..I believe the weapon i shot with flip up had the airsoft one that might be why I had such a suck ass time trying to zero in on 300 meter targets.Iam sure there are somegood ones i have not had the chance to play with any yet but i am stillopen to them.Be safe
Skintop,
Those sure look like it from here. Are they aluminum?
Was it these sights, by chance?
http://i76.photobucket.com/albums/j18/Skintop911/August%20Bushmaster/IMG_4370.jpg
Skintop,
Those sure look like it from here. Are they aluminum?
Yup.
It would be fair to say that they are...economized...in a variety of ways.
To put it bluntly they are shit. And BM charged us more than 199.00 a set when I had to order 25 sets to fix the missing or damaged sights we had. They only reason I did it was for maintaining consistency with the sights. I have since found other options that will be used.
Yup.
It would be fair to say that they are...economized...in a variety of ways.
UPDATE:
YHM sent me two thread taps free of charge as well as replacement pins for the barrel wrenches that were damaged recently. When I ran the taps into the holes and put the sight posts back in they worked. It would appear that they were in fact not threaded all the the way or there was some build up preventing them from going down.
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