Cleaning and general maintenance thoughts on Straight Pull AR platforms

[Zetter]

Hi All

I have after a load of waiting for a variation just got a 9mm AR straight pull for club use as I fancied something a bit different.

My question for those who have these type of rifle (and I know its a loaded question with no doubt loads of opinions) is what sort of cleaning regime do you use on them. With my bolt action hunting rifles I have generally done a full barrel clean with boretech eliminator and left them clean ready for next use but this is fairly straight forward i.e. bolt out cleaning rod and off you go.

However with the Straight Pull AR its side handle off bolt carrier group out ect ect. Do you do this every time or do a full clean every x number of uses to get rid of carbon build up?

Rifle did come with a pull through which I havent really used on rifles only shotguns.

Cheers Zetter

 

[Webley]

Mine do not have a side charger fitted so opening it up for cleaning is very simple. Two push pins and remove the BCG. I would recommend getting a bore guide for it. You can manage fine without one, but it makes it a little easier to get rods in and out without touching the receiver and keeps the fluids in the barrel.
I push the rear pin out, remove the bolt carrier group then split the upper and lower with the front pin. Put the upper on its back in the gun vice muzzle down, insert the bore guide and clean away. I clean after each shoot which is probably OTT. Barrel material and lining may vary how you want to do it.
I would not put a pull through in mine. In .22lr and .223, getting them out if/when the cord snaps is a pain. Being a straight walled pistol round with reasonable diameter I would suspect you would be OK with one TBH. I occasionally use one in my .44mag take down lever action.

 

[Zetter]

Cheers Webley

The issue on the schmeisser 9mm is it has a bolted in side cocking handle its going to be a bit of a pain to remove it every time to get the bolt carrier group out. I will do it for cleaning but also dont like the idea of unbolting a component bit every 5 minutes. I do prefer to clean the barrel every time tbh just to avoid any pitting. I didnt think of lever guns tbh I guess you have to use the pull through on them to avoid a major breakdown of the rifle to use a rod?

 

[Webley]

On most levers actions you would, mine is a takedown so the barrel is easy to separate. 8 turns or the loading tube, slide it forward 1/2" then turn the barrel and forend 90 degrees and it slides out of the receiver on interrupted threads.
Unbolting the charging handle on your AR is probably best minimised as it will wear the threads over time. If you have a torque wrench to reattach it you should minimise the amount of wear from over tightening at least.

 

[rarms]

What range are you going to be shooting it at? I assume fairly close range? What is the benefit to cleaning in in that case as accuracy will not really be an issue?

I wouldn't worry about cleaning it.

I don't think I have ever cleaned my .223 straight pull AR in the last ten years or so any more than a pull through. It has a stainless barrel though, but I doubt I would treat it any different if it didn't.

 

[MarinePMI]

Hi All

I have after a load of waiting for a variation just got a 9mm AR straight pull for club use as I fancied something a bit different.

My question for those who have these type of rifle (and I know its a loaded question with no doubt loads of opinions) is what sort of cleaning regime do you use on them. With my bolt action hunting rifles I have generally done a full barrel clean with boretech eliminator and left them clean ready for next use but this is fairly straight forward i.e. bolt out cleaning rod and off you go.

However with the Straight Pull AR its side handle off bolt carrier group out ect ect. Do you do this every time or do a full clean every x number of uses to get rid of carbon build up?

Rifle did come with a pull through which I havent really used on rifles only shotguns.

Cheers Zetter

In 9mm? I wouldn't even worry about being too fastidious with the cleaning. The 9mm doesn't generate enough pressure to cause serious copper fouling. Your biggest problem will most likely be powder/carbon fouling (or leading if you're running hard cast lead bullets). Just wipe things down and run a bore snake down the muzzle every 400-500 rds.

As to the action itself? Military trick: Baby wipes. It will soak up and swab out powder fouling like nobody's business. Just pull the bolt and wipe all the crud off the bolt carrier group. Wipe out the interior of the upper receiver, and then drop the bolt back in. Done. Since you have no gas system (since it's 9mm), you don't even have to worry about cleaning the gas key on top of the BCG.

I have a 9mm AR, as well as a Scorpion. I think I've cleaned them maybe twice in the last four years. They still run like a sewing machine (obviously mine are not straight pulls), and remain accurate. And both have had at least a thousand rounds (each) run through them.

BTW, 9mm AR's LOOOOVVVVVVEEEE 147gr bullets. Muzzle flip is actually less, since the recoil is slower and more gradual than a sharp (high velocity) 115gr or 124gr bullet.

JMCTW...

 

[jthyttin]

You're basically talking about cleaning a 9mm pistol. Rifle might collect more carbon at the breech face, especially with mod.

If you don't want to remove the sidecharging handle, you might try to coat the bolt (it's not really BCG in straight blowback) with some dry wax, to help in eventual cleaning (carbon etc. won't stick so much). Usually I'd recommend very light coat of graphite grease or similar, but this might require more frequent disassmbly, wipe down and re-apply. Idea is the same, prevent carbon sticking. When you do get the bolt out, clean the breech face including exctractor, and also back of the barrel. If there's carbon build-up, you might want to leave the bolt soak in diesel for few days. I'm sure there are also more sophisticated chemicals.

Regarding the bore, if the rifle is stored in room temperature, the bore doesn't really need cleaning for thousands of rounds. If you want to clean (protect) it, get a pull-through that has replaceable patches (Otis and others make these). Something like boresnake will only collect the crud. Beware that some brushes, mobs etc. might not fit / be able to align to the bore w/o removing the bolt. Oily patch after shooting session and bare patch before the next session should be plenty.

 

[jthyttin]

Cannot edit the previous post. I have some kind of blind spot for AR style straightpulls, of course 9mm is not blowback! Tried to watch some videos, but SP-9 is niche product and no reviewers touched on the most interesting part, i.e. how the breech works. One guy managed to go as far as pulling the charging handle back, it seems there actually is BCG and separate bolt.

Since (both) charging handle(s) manage to open the breech by simply pulling, there is some kind mechanism that keeps the breech shut when pressure is applied to breech face, but allows opening when BCG is pulled back. That mechanism is probly the weak spot re: cleaning, especially since it's one of a kind with no track record. I still guess it takes several thousand rounds worth of carbon/other crud build-up to get it to malfunction.

I don't know what type of shooting you do at the club, but obviously leaving sidecharger off and using regular charging handle means you can disassemble it as easily as regular semiauto AR.

 

[Zetter]

Cheers for all the suggestion all its been really helpful. I am not adverse to taking the side charging handle off for a good clean every so often but taking it off every time I come back from the range doesn't seem the best plan simply from the point of view of continually undoing the bolts and doing them up.

Seems like the best plan is a pull through regularly and as MarinePMI says a decent clean every so often.

I think I got too hung up on cleaning the way I do with my bolt actions which are a bit of a different item really.

 

[Webley]

Cannot edit the previous post. I have some kind of blind spot for AR style straightpulls, of course 9mm is not blowback! Tried to watch some videos, but SP-9 is niche product and no reviewers touched on the most interesting part, i.e. how the breech works. One guy managed to go as far as pulling the charging handle back, it seems there actually is BCG and separate bolt.

It is a BCG as per a gas powered non straightpul. But without the gas key or internal gas chamber to seperate the bolt from the group. The standard charging handle and optional side charging handle act on the BCG moving it backwards. This rotates the cam pin, rotating the bolt 30 degrees and unlocking it from the barrel. The profile of the cam maybe different to aid unlocking on straightpull with fired brass in the chamber. Once unlocked the BCG drags the bolt back from the breach and ejects the brass. You let go of the charging handle. The BCG is then forced forwards by the buffer spring, picking up the next round from the mag the same as a semi auto.
Pretty much the same as first round load on semi auto AR TBH. I would guess they have changed the bolt and cam path to suit 9mm.
This shows the operation with gas system.

 

[Jagdmatch]

I am guessing it has an AR style bolt head as without it might just be a blow back! These work well

Breech Tool Lite 5.56 mm Cleaning Aid

The new Breech Tool Lite has been developed from the ever popular Breech Tool to give you a lightwesight and compact solution to cleaning your rifle.

www.googleadservices.com

 

[MarinePMI]

It is a BCG as per a gas powered non straightpul. But without the gas key or internal gas chamber to seperate the bolt from the group. The standard charging handle and optional side charging handle act on the BCG moving it backwards. This rotates the cam pin, rotating the bolt 30 degrees and unlocking it from the barrel. The profile of the cam maybe different to aid unlocking on straightpull with fired brass in the chamber. Once unlocked the BCG drags the bolt back from the breach and ejects the brass. You let go of the charging handle. The BCG is then forced forwards by the buffer spring, picking up the next round from the mag the same as a semi auto.
Pretty much the same as first round load on semi auto AR TBH. I would guess they have changed the bolt and cam path to suit 9mm.
This shows the operation with gas system.

9mm AR's don't have locking lugs or a bolt like a standard AR. Completely different system. I'll post a picture here in a minute...

 

[MarinePMI]

 

[Webley]

In other countries no. But in the UK they can't be blow back as we are not allowed semi auto, apart from .22lr rimfire and shotguns. Hence straight pull and I think using the same as a 5.56 AR bolt.

 

[MarinePMI]

Just a guess, but I'd imagine the side charger for the single shot versions you guys have, is what locks the bolt into place, keeping it from cycling the next round into battery.

But in the normal AR-9's, they're a blowback design. Well, technically they're delayed blowback, but that's another argument.

Perhaps the OP can take a picture of his bolt? It'd be interesting to see if it is indeed a regular bolt. I suppose it's close enough in diameter, but I'd wonder about the length of the cartridge and feeding. <shrug>

 

[jthyttin]

Most usual 9mm AR is straight blowback (inertia only), like pictured by Marine.

Then there are delayed blowback, at least rotating bolt and MP5 style rollers have been used (actually they're genuine H&K parts).

There are also 9mm gas guns, but they're rarity (and finicky).

From what I've seen in the videos, SP-9 uses none of these designs. The bolt head definitely not resembles regular rotating AR bolt. The sidecharger has no function locking the breech, you can use the gun w/o it.

Bullet weight will probly have quite less effect on straightpull vs. straight blowback, since on semiauto most of the gun movement comes from heavy parts moving back and forth.

 

[Zetter]

It does look like an AR bolthead tbh with the multilug when I pulled it to give it a quick clean last night. I will get a pic and post it the next stripdown I do.

 

[jthyttin]

Browsed through few more videos, yes it seems there's maybe 3 lugs. In previous video the angle was such it looked different.

Maybe they needed to eliminate lugs on the bottom to get it to feed from single feed Glock mag, and then decided to eliminate few more lugs. AR-15 bolt itself would work with double feed magazine (case head diameter is same).

And yes, design is very simple using the original rotating bolt principle.

 

[MarinePMI]

Browsed through few more videos, yes it seems there's maybe 3 lugs. In previous video the angle was such it looked different.

Maybe they needed to eliminate lugs on the bottom to get it to feed from single feed Glock mag, and then decided to eliminate few more lugs. AR-15 bolt itself would work with double feed magazine (case head diameter is same).

And yes, design is very simple using the original rotating bolt principle.

I'm guessing they just have a special/custom barrel extension. This would make sense with a three lugged bolt, and address the feeding issues you mentioned. Plus, it allows the gunsmith to turn a standard 9mm barrel blank into an AR profile without a whole lot of hoopla.