Powder Ignition Test Arrowhead Plug: No sealing Shoulder

[Deleted]

DO NOT TRY THIS!!!!!!!

First off, Luke did not ask me to do this test.
Secondly a big thank you to a great friend of mine who made the shoulder less Arrowhead 209 Plug.

Rem 700 ML
26" .458 Brux barrel
Harrel Brake
70 grains of H4198
310 APB
CCI 209 M Primers
Arrowhead 209 plug

I wanted to do a test to see how well the Arrowhead plug would ignite powder without a sealing shoulder on the plug.

I didn't use Teflon tape
No sealing paste
I cleaned the plug off with an air compressor nozzle to make sure it was super clean and nothing would hold the gases back upon ignition.

Velocities were: 2841, 2848, 2828 I brought the gun directly from the safe and shot it, so the temps were ~ 65-70* I'd say
Velocity from my other thread where I backed the plug out keeping the sealing shoulder lifted. 2823
Velocities from the shoulder seated. 2826, 2813, 2823 @ 50*F

There wasn't any blow back in my face.
there is no signs of gas cutting on the threads
The plug threads had black marks on them about 8 threads back. (my other plug has them about 10-11 threads back, but it has a couple hundred shots on it.

Ya, I know edge, it's only 3 shots and the sample size is small, but I think it works well.

[Deleted]

Very cool! Still boggles my mind, but the proof is in the pudding!

[Jon]

Well done. As myer129 said the proof is in the pudding!

[epanzella]

The threads in this example are not sealing but rather controlling and slowing the leak much the same way that the long flame channel in a Savage plug protects the primer from bulging due to smokeless pressures. In a Savage when the chamber is at peak pressure it backflows thru the flash hole into the flame channel. The flash hole being only .030 slows the backflow of pressure so that by the time the flash channel fills to capacity and pressure starts to rise the barrel pressure is dropping and the primer is protected. The flash hole is not a seal but merely a choke point to buy time. I believe threads act the same way, not sealing but slowing the gasses until peak pressure is dissipated. As it is impossible for a non tapered thread to have zero clearance, I don't see how this could work any other way. The fact that the first 8 threads were discolored seems to support this.
Ed P

[Deleted]

Earnhardt,
Does the front of this modified plug contact the barrel? Kyle

[Deleted]

kyle, I screwed the plug in until I felt it bottom out, and then I screwed it back away from the barrel.
So only the plug threads were making contact with the barrel.

I used a .040" bushing, like I have been for a while.

I cleaned the threads off as much as I could to let as much gas back as possible. Like I said, no thread tape or paste either. I only wanted the threads to be a seal for ignition.

Of course the threads don't seal the load 100%, especially over long periods of time. But when we are talking 6-8 milliseconds of powder burn time, the threads alone seal it for ignition.

As for the first 8 threads having debris on them, it's the same on my shouldered plug, the threads have debris on the first 11 threads or so. But that plug has a couple hundred T-Rex shots on it.

[Deleted]

I'd like to see the results of an extended shooting session instead of a three shot sample, maybe even on a YouTube video. Thanks, Kyle

[Jon]

Interesting! Keep up the good work. Not at all surprising. Like was stated before the threads are a loose seal (for lack of a better wording) You are only talking milliseconds.

[Richard]

You know what? You have proved the point! Why even go any further? We are going to be using the plug WITH the shoulder and some sort of anti-seize or teflon tape anyway? Further testing without the shoulder would seem like a waste of good bullets and powder...............Well Done!
Which also tells you why I have not been getting any leakage past the first one or two threads with my Savage plugs even though it is evident gas is getting past the forward sealing shoulder? Fact is.............They both work. And Luke's is easier to machine for!
So, just because you have a rifle with the Savage type plug...............you are still in good shape!
Richard

[a1smokepole]

I would like to see the plug taped from the bushing end with some over the end at the bushing to the should just to see how that seals.

[Deleted]

Mar 28, 2015 11:55:32 GMT -5 hankinsrfls said:

It is absolutely ridiculous to think this modified plug would hold up over the long haul.. There's nothing holding it in place to maintain headspace and or a consistent primer seat..... If you shot this plug for a long period of time it would without a doubt start leaking all the way around the threads and cause gas burn and erosion and eventually ruin the barrel threads.

Like Epanzella said... That many threads slow down the pressure long enough for the bullet to exit the barrel, the longer you use that plug the farther the gas will get and sooner or later it will blow out the back end of the plug.

The sloppier the fit between the threads of the plug and the threads in the barrel, the faster you will get the leak.

Thanks Jeff Hankins.

But it still sealed up the barrel to ignite the powder, with just the threads and no sealing shoulder.

And very efficiently I have to say...wouldn't you?

[Jon]

I going to leave my horse out of this race. I think it defiantly did prove a point leave it at that!

[Deleted]

I'll admit I was one that didn't fully understand the theory of the threads sealing when edge told us that's how it works. I didn't take part of the poll but I was like that sucker is nuts! I'll eat crow... EDGE was right and a lot of us doubted him, a little experiment shows that for our case the threads provide a good enough seal given the duration of the pressure. Kudos to edge and Earnhardt for standing their ground!

[bestill]

Seems to me machine threads don't seal at all . They restrict flow

[Dave W]

So, if you use a hatchet to cut the threads, like these.


Would it have any affect on restriction or sealing?

Good test Earnhardt!

[Jon]

myer129 kyle and others. Well put. That is what PM's are meant for. If it is a concept. then go for it. Everyone can gain. As was stated safety comes first. I would have to say The traces being done are a great advancement work and expense. Like was stated before I was here in the little gun days. At least to me it seem the more you fed it the better it shot. But I'm sure some of us stretched the point too far. We were lucky the guns we were using were over built. So I can fully understand TG statement he doesn't know what gun you are shooting or what has been done to it or by who. CYA never hurt anyone.

[Deleted]

fact is this
try that with a Savage plug and you WILL get blowby all the way out the back, been there, done that. larger dia with many less threads to get past.
why does this work on the new plug? smaller dia and more threads to get past..

Jeff made his point with the air test, Josh and Edge have made their point as well. We have learned from both..
Personally, I just know what works and what don't through experience.

All of this arguing and Groupie accusation stuff has me worn very thin. reminds me of a bunch of old women always wanting to get the last word.
I have decided that after tonight Im taking a 30 day break from the board and if things are no different when I visit back then I will leave for good.

I have made some good friends in the last seven years and learned a good bit as well but this place is getting just like the other forums I visit sometimes. most could probably care less if people leave, me? friends miss friends when they depart...Bill

[Deleted]

Mar 28, 2015 15:05:16 GMT -5 @sml said:

E thanks for your testing....it was thought for the longest of time that the earth was flat,lol....Now how well would a higher tpi plug perform..?

sml, Great question.
I don't know.
I would assume having a higher TPI would help the "sealing" capability.
About the same as adding a longer plug with more threads would.

But when it comes to the strength of a higher TPI vs. lower TPI, I have no clue.




You guys need to realize that this is a test. That's it.
I proved the plug would ignite the powder with threads only. If it wouldn't have ignited the powder...we probably would be arguing about that too.

Trust me, I've tried about all there is to try with these SMLs.

Some worked, others didn't

But this test gives me total and utter confidence in a rear sealing plug, that has a fair amount of threads in front of the shoulder.

(Don't take this the wrong way now guys) We know the 209M primers add way more pressure to a load than a LRM.

Maybe that's the only reason why it worked.
Maybe there is unseen blowby, or pressure loss, that is only made up for with the added pressure of a 209M primer.

I don't know.
But it's very obvious that when a shoulder is added to these plugs, whether LRM or 209, the seal is perfect.

How do we know this? When we remove the Arrowhead plug, and I'm guessing the sealed LRM systems also, there is no debris on the sealing shoulder. None

Over time will this shoulderless plug gas cut or fail in some way? I don't know.

But, if I were to put some pipe tape on the threads, I'd be very surprised if any gas cutting occurs.
The only variable at that point would probably be the plugs' ability to work itself loose from pressure or the twisting motion of loading/unloading a tight 209M primer in to it.

A lot of guys gave me crap when I started the "Weakest Link" thread a couple for years ago wondering why we were still using vent liners and not a stronger material that would last hundreds or thousands of shots. Just because someone says that "this is the only way something works" I question it. Almost all of the time.

Guys think of what's coming out next.

Hankins is coming out with a Sealed 209 module ignition system.
Am I doggin' him for that?

Heck no! I cheerin' him on. We will all benefit from his 209 system whether we are using it or not.

How? Sooner or later info will trickle out with posts and threads telling us how things are working for him. As well as velocity and accuracy data.

How do I know that his HIS 209 rear sealing system is going to work great? Trust me I know.
Almost all the data I'm getting from the rear sealing Arrwohead 209 plug is different (better) than the Savage plug. WHEN THE PRIMERS ARE FITTED TIGHT... throw that d**n "C" bit away guys.
Some subtle differences, some drastic. Especially with slow powders. With standard loads to mid-range loads the Savage plug is fine and works great.

Out of all of the various squabbles we've had on the board, this is what drives me crazy.
Any threat to someone's belief system or thought process due to a new "invention" or test that comes out, and people go nuts.

A lot of the time the most push back comes from guys who shoot their guns very little or not at all. Don't take this the wrong way, either go burn some powder, or walk away from the keyboard.

For all the guys I've worked with on this boards over the last several years know one thing about me. I will take any idea anyone has and put it to the test.

No idea is too crazy or stupid, until it's proven wrong. Nothing is set in stone with me. That's the way I am, and I will not apologize for it.


Sorry guys, if it works it works.

[Deleted]

Earnhardt, have you used one of Luke's production plugs? If you got a primer in that baby without any lapping or polishing I'm very impressed! I found them to be tight enough to need to be polished to suit your needs.

[Richard]

I just finished one on my latest build (with Luke's plug) and it did need a little chucking in the lathe and a dowel and some 400 grit to just slightly open it. It still took a good slam down on the bolt handle to seat it but I told the customer as much. At least I think I did........right Joey?

OH, BTW, how about we RE-VISIT TRIPLEX LOADS
Richard

[Deleted]

Mar 28, 2015 20:24:49 GMT -5 @myers129 said:

Earnhardt, have you used one of Luke's production plugs? If you got a primer in that baby without any lapping or polishing I'm very impressed! I found them to be tight enough to need to be polished to suit your needs.

The first plugs had primer pockets were machined tight, so we could open them up just enough to get a snug primer fit.
The last ones I've got have been opened up a little more. They are actually perfect.
It was Mike's idea to start tight and slowly open them up to see what size primer pocket worked best.

If you have one of the first plugs, slowly open it up, BY HAND, with a small dowel with sandpaper, or a chainsaw sharpening bit.

The new plugs are pretty much dead on.

[Deleted]

Tri-plex loads?...Go for it!

[Deleted]

Mar 28, 2015 20:58:00 GMT -5 Richard said:

I just finished one on my latest build (with Luke's plug) and it did need a little chucking in the lathe and a dowel and some 400 grit to just slightly open it. It still took a good slam down on the bolt handle to seat it but I told the customer as much.

Richard....
Did you have to open it up using a winchester primer..I just received a new Brux with Lukes new plug today...Seemed to me the primer fit with a winchester primer was going to work without opening it up...Just an observation, don't have the gun assembled yet...By the way, I'm impressed with both the Brux barrel and the new plug...Both fit and finish...Barrel is consistent from top to bottom...
Thanks, Luke
Zen

[Jon]

Earnhardt. I'm one of those that can't get to the range much. But I appreciate any and all testing done. Believe me I would rather be out there doing the testing. It is just not in the cards for me so I really appreciate any testing done by others!

Hillbill. I for one would hate to see you leave. You have been a great contributor. Just read between the lines there is still a lot of info to be gained.

[Deleted]

Mar 28, 2015 16:42:23 GMT -5 Dave W said:

So, if you use a hatchet to cut the threads, like these.


Would it have any affect on restriction or sealing?

Good test Earnhardt!

What kind of plugs are those?

[cowhunter]

Earnhardt, now I understand and appreciate the test better. I like your scientific approach.

[Deleted]

2nd Test

Rem 700 ML 26" Brux barrel
Shoulderless Arrowhead plug
310 APB
70 grains of H4198
CCI 209 M primers

Plug was not seated against barrel.
No tape on threads
No paste on threads
Only the threads were stopping gas blow back

I took more time between shots to try to keep barrel at same temp when I shot.

Velocities: Over Magnetospeed
2860
2857
2853
ES-7

I going to leave the plug in and shoot 3 more groups for a total of 5-3 shot groups, 15 shots total, with the shoulderless Arrowhead Plug.

[Deleted]

Test is proving to be very repeatable. Nice ES for a loose plug!

[Deleted]

3rd Test
same load

2872 jack hammer down the barrel since it was caked up from sitting.
2816 loose
2845 just right....

2 more groups to go...

[Deleted]

4th test

same load and gun

2840
2847
2846

One more test to go....