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Sharkbait

Rifle length gas port or the +2 on a 22’m barrel

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Hello everyone.

I’m just now starting to order parts for my 1st lr308 build in 6.5 cm. My plan was to use a 22’’ Kreiger barrel. I’ve been reading a lot of +2 talk on gas port. I spoke with I believe Kevin from Kreiger today and also received an email from compasslake engineering stating the plus 2 isn’t necessary. 
I’m wanting to build right the 1st time and am asking the experts for guidance 

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I have a plus 2 on a 22” 260 rem build that needed the gas port opened up to function properly with real 308 recoil components installed. Dwell time and port size are the key items, you can make a rifle length gas system work on a really long barrel (long dwell time) but the port needs to be smaller or the gas system needs to be chocked down somehow. Whichever way you go if you deviate from the original dwell time you are going to have to compensate for the difference and that can get complicated fast. Rifle length gas and 20” barrel or +2 gas and 22” barrel have the same dwell time. This is of course depending on cartridge pressure so if you deviate from the standard 308 that press can change which can affect your gas pulse from the standard dwell time. I’m not trying to confuse you and may have thrown too much info at you without the background gor it but it shows how easily things can get complicated if stoners orig design values are changed just so a company can sell some newer cheaper part. 98z5w and the rest of the guys here have a shoot load of experience with this stuff and can make recommendations to get you lined out. It is up to you to read what they say ask questions to make sure you understand and take their advice and move forward. If you are not open minded enough to do that then the guys won’t waste their time.

not trying to scare you off just settin the stage sorry for the long post and Welcome to the fun zone.

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Thank you both. When I emailed with Frank at compasslake engineering, he stated that since they will drill the gas port, that they will drill the +2 at no extra charge. I’m good with that. I guess now I need to determine size of hole, gas block, correct gas tube and buffer system. All my ar15’s run with the jp silent capture.

when I was looking at compass’s website, the do also offer a head spaced bcg, it’s an A.P. bcg. Think this will be okay or purchase the jp full mass and send in to have configured with my barrel.

Now, if I go to Kreiger website, they do headspace a jp bolt to the barrel, and that acted like I was nuts when I asked about the +2 gas port. When you order your barrel from them, they pretty much want you to send in your upper to headspace barrel and bolt and will fit your muzzle device also.

i did NOT get into this thinking i was going to build on the cheap, use cheap parts. I didn’t do that when building engines, won’t do it building guns. I sure didn’t start this project to save money, kinda like buying a truck for gas mileage.
so order a Armalite gas tube? But first I would need to measure the length from the port to gas key? 
Same with buffer system. Also order that from Armalite? Any recommendations on part numbers. I’m running A.P. M( set up.

again, thank you all

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1 hour ago, Sharkbait said:

So I found a website..... heavy buffers.com. Seems to be saying everything y’all have talked about on the back end of my build. Is this a place y’all know?

It's not just a place we know, but a place we love. I bought a heavy buffer from Clint less than two weeks ago. He's good people and will treat you right.

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Not sure if you necessarily need the +2 gas system or if you will see much of a difference when compared to a rifle length system - but I don't know.  I have a 24" barreled .243Win with rifle length gas tube and adjustable gas block that I built for long range shooting and 1000 yard events.  My X-caliber barrel came drilled with a .0625 gas port but I had to open it up to .0935" to get it to function correctly - guys on this site helped me resolve that issue.  Besides the adjustable gas block, I have standard LR308 gas, BCG, and rifle length buffer/buffer spring parts.  It fires hot 95 grain handloads consistently and hasn't had a stoppage/malfunction since resolving the gas port size over two years and about 750 rounds ago.  I may try a heavier buffer in the future just to compare but in my experience with the 3 LRs I have (.308, .243, and 45 Raptor) I didn't need one to make the rifles function correctly.  

I am interested to hear how the +2 gas system and the heavy buffer works for you, keep us posted.    

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You don’t have to do the +2 gas system. You need to be careful what parts you pick because there is no standard for the large frame ar. Some parts are not compatible with all the available patterns and parts. Armalight is good stuff but some of it only works with armalight receivers which are pretty pricey and may be hard to find. Don’t go hog wild and end up with a pile of incompatible parts. Lr308 implies dpms and much is not compatible with armalight. Get a list of what your thinking together and let the experts weigh in on how well they will work together. We have guys that prefer armalight and guys that have done something with pretty much any available pattern. Go slow and make sure you are chasing the right stuff

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46 minutes ago, Radioactive said:

You don’t have to do the +2 gas system. You need to be careful what parts you pick because there is no standard for the large frame ar. Some parts are not compatible with all the available patterns and parts. Armalight is good stuff but some of it only works with armalight receivers which are pretty pricey and may be hard to find. Don’t go hog wild and end up with a pile of incompatible parts. Lr308 implies dpms and much is not compatible with armalight. Get a list of what your thinking together and let the experts weigh in on how well they will work together. We have guys that prefer armalight and guys that have done something with pretty much any available pattern. Go slow and make sure you are chasing the right stuff

 

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So,I just emailed Clint from Heavy Buffers to help with extension and spring and buffer. Was planning on running a Jp full mass bcg. 

Arguments valid, and make dang good sense on the plus 2 or standard rifle.. leaning towards the plus 2 tho. Added insurance I guess. not exactly sure how to figure gas port diameter. Would think towards the 9’s and can use block to help control. Deciding on a vltor adjustable block or a superlative arms block, either, in the low pro .936. Barrel, kreiger 22inch, Aero Precision M5 and aero lpk.  Vg6 Gamma muzzle device. Still deciding on trigger. 

And that’s where I’m at with what little I know

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Just now, Sharkbait said:

superlative arms block

Read the reviews here, in my experience the Superlative did not have enough room on the bypass side to make a difference for the 308 and that was a 16 inch barrel rifle gas system, I would assume the Creedmoor would have a similar issue with too much gas for the bypass mode. Without the bypass mode it isn't any different than the cheaper restriction type blocks. I emailed Superlative a couple times asking about this but never got a reply, figure I had my answer.

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7 minutes ago, Sharkbait said:

 Aero Precision M5

DPMS pattern so watch out with armalight parts I believe @98Z5V built a dpms Pattern gun with mostly armalight parts- not sure what hoops he had to jump through to build it. I thought you mentioned kreiger not wanting to do a +2 gas length. Other barrel makers out there that do fine barrels. 

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10 minutes ago, jtallen83 said:

Read the reviews here, in my experience the Superlative did not have enough room on the bypass side to make a difference for the 308 and that was a 16 inch barrel rifle gas system, I would assume the Creedmoor would have a similar issue with too much gas for the bypass mode. Without the bypass mode it isn't any different than the cheaper restriction type blocks. I emailed Superlative a couple times asking about this but never got a reply, figure I had my answer.

Good to know. Appreciate the info

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1 minute ago, Radioactive said:

DPMS pattern so watch out with armalight parts I believe @98Z5V built a dpms Pattern gun with mostly armalight parts- not sure what hoops he had to jump through to build it. I thought you mentioned kreiger not wanting to do a +2 gas length. Other barrel makers out there that do fine barrels. 

It’s not that they won’t, when I mentioned, what’s told that had never been brought up. Now that was at kreiger themselves. Frank at compasslake was kinda the same but said they would drill the plus 2 if I wanted it.

im not dead set on Kreiger either. I’m really only looking for 2 things outta this build. Reliability and accuracy. Those 2 things to me are what makes a rifle sexy(if that’s even a thing)...

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I'm using SLR Rifleworks Sentry 8 (.875") adjustable gas blocks in both my .243 Win and 45 Raptor rifles. Melonite steel on the .243 and titanium on the 45 Raptor.  Both have great adjustability and the customer service is exceptional.       

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8 minutes ago, BIGTRUCKNUT said:

I'm using SLR Rifleworks Sentry 8 (.875") adjustable gas blocks in both my .243 Win and 45 Raptor rifles. Melonite steel on the .243 and titanium on the 45 Raptor.  Both have great adjustability and the customer service is exceptional.       

Good to know. I’ve been looking at their products. Everyone is outta stock on them.

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7 minutes ago, jtallen83 said:

I would second SLR. Great product, great customer service.

I third them, they've become an integral part of any new build that will end up suppressed.

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37 minutes ago, Matt.Cross said:

I third them, they've become an integral part of any new build that will end up suppressed.

Now that you’ve posted in this thread, can we move it out of the contest section and into a more relevant location?

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1 hour ago, DNP said:

Now that you’ve posted in this thread, can we move it out of the contest section and into a more relevant location?

It's done. Aren't you a Moderator? Or is this a social engineering attempt to elevate your privileges?

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7 minutes ago, DNP said:

A who?  Nope. Just the A-hole with OCD who likes to point out potential issues. 

That's a terrible oversight on my part, and will be remedied with a quickness.

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