hk msg90/psg1 half moon locking rollers

[black_ump]

not sure why they use them, not sure how they stay in the bolt head eaither... any one with insight on this ? might switch to them as well as the t30 or t23 locking piece if its worth the investment.

waiting on my approvle to be a member of hkpro.com so bare with me

 

[Guest]

Rollers that don't roll.......why bother?

I have had many discussions with Mike @TSC Machine when he was making a custom 11E build for me. To combat bolt bounce, I went with an MSG90 carrier and thus an MSG90 bolt head so it would match up with the extractor cut in the 21E barrel

Basically, they are a pain and should be avoided unless you have more money than you know what to do with. Why? They are rollers that don't roll...which doesn't make much sense. Mike told me that they typically use 93/33 bolt heads if they can for any 5.56 projects.

During the course of my build, one of my half-moon rollers shattered on a test fire. I can't remember if it was a +4 or what, but the one needed to replace it was darn near impossible to find and I was half a step shy of having to buy another bolt head just to get the rollers. Thankfully, Adam Weber has some now at $275 for a pair....which is still awful.

One thing Mike told me to do was to pack the rollers with grease and make sure they are lubed at all times to increase their longevity.


Depending on what you are doing, you're probably better off sticking with the traditional roller system for ease of replacement parts. No sense making things harder and more expensive on yourself if you can keep it cheap and easy.

I also wouldn't recommend swapping locking pieces at random either unless you are 100% sure of what you are doing. Plus certain locking pieces will only work with certain firing pins and carriers.

What exactly are you trying to accomplish?

 

[black_ump]

Re: Rollers that don't roll.......why bother?

i simply want to know why.... and if its worth it buy it... i want to get my msg90 clone up to its accurace potential. if the locking piece will unlock quicker or slower and aid in accuracy then it might be worth testing. if half moon rollers will last longer then its worth a try...

i like the full roller but i belive the steel choice would be better if they used titanium or somthing harder like inconel instead of the mild steal.

so mainly just currious

 

[Guest]

Re: Rollers that don't roll.......why bother?

As you can see, "harder" isn't always the best medicine. I can't say that i've ever seen one of the steel rollers shatter the way that titanium one did.

I'm almost positive they won't last longer for you. Because they don't roll, they just rub and create friction every place they make contact. Friction equates to wear.

And regarding locking pieces, read:
http://hkpro.com/index.php?option=c...ocking-pieces&catid=4:special-topics&Itemid=5

If you're searching for accuracy, you're not going to gain much in this area. If you want to do a do a true to spec MSG90 clone build, by all means go for it. If your goal is accuracy, there are other areas where you might want to redirect that $1300.

The boy's over on the pro will tell you the same thing I am. In fact, i'll chime in there too, if you don't believe me

.

 

[Guest]

Re: Rollers that don't roll.......why bother?

Oh, yeah. You would also need a different ejector. And don't forget you need to have a recess cut into your barrel for the larger extractor.

I see that you already have this thing built and you're already painting it. I would just stick with what you've got.

 

[black_ump]

Re: Rollers that don't roll.......why bother?

i did know about the extractor cut in the chamber face... and i have debated on my next barrel ( mike rock polly rifled barrel would that be called a 5r ? ) doing this cut and getting one of these bolt heads.

i dont think their is much more i can do to this gun to aid in the accurace department, the barrel is floated the receiver has been reinforced with the rails.... i have the match psg1 trigger.

only thing is maybe later on getting a better barrel..... i hear it all starts at the barrel

 

[Guest]

Re: Rollers that don't roll.......why bother?

5R and polygonal are 2 totally different animals. Poly is the traditional way for the HK purist, but not necessarily the most accurate.

Once you get onto HKPRO.com, there is a fella "JFK" that has built his own parts for PSG-1 clones. He has/had a thread on the step by step process of his precision MSG style build. Very informative, and I think he is getting good accuracy.

If you grow weary of the PSG-1 trigger, there are better options out there. I prefer the Williams Set trigger, if you can find one. Another option is the very rare G3SG-1 type group with the set option. I've heard some rave reviews on that, but there might be some legal ramifications because of the nature of the pinned grip.

It seems that you have a fairly stable base, which is one of the downfalls of the roller lock platform.

While I know you do expect good accuracy from a rifle of this nature, anything sub-moa is excellent.

 

[black_ump]

Re: Rollers that don't roll.......why bother?

oh well i will do sub-moa lol dont worrie..... i may need to tinker it may take me all summer but ill get their... i think the psg1 trigger is rather smooth yet.. its rather sensitive

so what is 5r ? and which will yeild more accuracy the polly barrel from mike rock or a button rifled barrel ?

 

[Guest]

Re: Rollers that don't roll.......why bother?

Here is the build I was referring to:
http://hkpro.com/forum/showthread.php?79385-MSG90-hybrid-in-progress&highlight=

And as for the rifling....

I only know the basic differences.

5R uses 5 lands and grooves that and does not used the sharp edged rifling that standard rifling does. Obermeyer developed it for 7mmRM I believe. Krieger does it to Obermeyer specs. Many others do 5R as well. I'm not 100% on the actual benefits/drawbacks. Might create a tighter seal

Single point vs. Button: While most lean toward single point due to the slightly less variance. Button rifle barrels have won their fair share of competitions and should not be thought of as inferior.

As for Polygonal is supposed to provide a better gas seal on the bullet.

For the most part, I'm pretty sure that the actual rifling is less of a factor than the shooter.

 

[black_ump]

Re: Rollers that don't roll.......why bother?

thanks for that link for some reason its taking them forever to approve my membership over their.....

in that case ill get a rock polly rifled barrel if the rifling isnt that big of a deal then ill get the more authentic to my build...

ya i never under stood how the half moon rollers worked since they really cant roll lol idk

 

[Guest]

Re: Rollers that don't roll.......why bother?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: black_ump</div><div class="ubbcode-body">thanks for that link for some reason its taking them forever to approve my membership over their.....

in that case ill get a rock polly rifled barrel if the rifling isnt that big of a deal then ill get the more authentic to my build...

ya i never under stood how the half moon rollers worked since they really cant roll lol idk </div></div>

....cause you're already very well known there. Weren't you banned?

 

[harlikwin]

Re: Rollers that don't roll.......why bother?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Pointblank4445</div><div class="ubbcode-body">5R and polygonal are 2 totally different animals. Poly is the traditional way for the HK purist, but not necessarily the most accurate.

Once you get onto HKPRO.com, there is a fella "JFK" that has built his own parts for PSG-1 clones. He has/had a thread on the step by step process of his precision MSG style build. Very informative, and I think he is getting good accuracy.

If you grow weary of the PSG-1 trigger, there are better options out there. I prefer the Williams Set trigger, if you can find one. Another option is the very rare G3SG-1 type group with the set option. I've heard some rave reviews on that, but there might be some legal ramifications because of the nature of the pinned grip.

It seems that you have a fairly stable base, which is one of the downfalls of the roller lock platform.

While I know you do expect good accuracy from a rifle of this nature, anything sub-moa is excellent. </div></div>

With regard to the triggers, I think williams is the way to go. Especially with a parts gun, you need to worry about parts count. The Williams set trigger is pretty good, though a bit of a pain to operate the set feature. He now also makes a clone of the G3SG1 group with the button that works really well too and looks correct for a G3SG1.

FWIW I have a msg-90 with just a regular bolt head and its a sub-moa gun. I debated using a msg-90 head for "accuracy" but decided it really wasn't worth it.

 

[Goot]

Re: Rollers that don't roll.......why bother?

All this talk about these rifles makes me question if I should sell mine!

 

[cyrekzz]

Re: hk msg90/psg1 half moon locking rollers

I joined HKpro 4 months ago - still can't post anything... i think the locking piece on my SR9 is a pain in the ass - I need a pliers with rubber teeth or I put it in backwards sort of hard and got it to "open". it's that spring with the lever that rides on the collar that's so stiff. Damn...