Arrowhead Plug

[lwh723]

Well, today I got to put the finishing touches on a project that started at the end of last summer.

The project was a 9/16-18 threaded rear seal 209 plug. They will be fit for bushings and can be removed with a 7/16 hex head.

Couldn’t have done it without the help of Airborneike. And Earnhardt was also a major testing contributor.





Some advantages are as follows:
-The smaller diameter results in less barrel being removed. After seeing the mechanics of a barrel rupture first hand (pun not intended, Edge), my opinion is more barrel around the plug is really important.
-Rear seal isn’t prone to gas cutting
-Threaded for over 1.25”
-Smaller diameter than other plugs means less surface area for pressure to act on--which means, less force on plug.

We have been running this plug in several guns with great results (my brux build, Earnhardt’s B17, and several others). Even though, on paper, the plug should be able to withstand more pressure than any other option out there, I wanted to do some proof testing just as a safety check.

So here’s some of the over charge testing I did. Test barrel was a 442/450cal 24.5" green mountain barrel.

All shots were with 300gr XTP, 0.060veggie wad, and CCI209M, 0.030” bushing

Shots 1-3 (didn’t upload video) 100gr H4198
Primer normal looking and easily removed. Plug easily removed. Barrel not bulged.
Shot 1: 2912
Shot 2: 3121
Shot 3: 3136

Shot 4 140gr H4198
Primer slightly extruded into firing pin hole. Plug easily removed. Barrel not bulged.
Shot 4: 3612 FPS (QL says 105Kpsi and 3680FPS)



2 – 100gr primers on left. 140gr load on right.


Shot 5, 210gr H4198
Shot 5: 3930 FPS (QL says 137Kpsi and 4030FPS)
Primer failure. Plug stuck in barrel. Barrel bulged for 3” at breech. Recoil lug snapped. (Was still able to remove barrel from action.)



Snapshot of video. Notice smoke coming out muzzle and action.



Toasted primer


Snapped recoil lug




Just for fun, assuming 10lb gun, here’s some recoil numbers.

Normal 70gr H4198 load with 300gr bullet at 2700 FPS: 38 ft-lbs
100gr H4198, 3136 FPS: 57 ft-lbs
140gr H4198, 3612 FPS: 86 ft-lbs
210gr H4198, 3930 FPS: 129 ft-lbs



Edit to address questions that have been asked:

1) Price/Availability. $55 + bushing cost. First small batch due this week (all spoken for) after that will get another run done. So 3-4 weeks out.
2) Retrofitting barrels: I think all of the other plugs out there are 5/8” or bigger, so it’s going to require shortening the barrel to retrofit.
3) Edge, I haven’t been able to get the breech plug out yet. Based on how it feels, I think it’s just stuck at the end. Assuming pressure got in lockring area and swelled end of plug? In any event, I’m definitely open to sending barrel out for FA.
4) Cowhunter: I’ve only beening using 70gr of H4198 with my 310APB, but Earnhardt has been using a lot of other loads. Similar flame path to Savage BP, so same primer situation
5) I, like Earnhardt, have been having no issues with ignition and single powder loads. I have been using the 0.040” tungsten bushing exclusively.
6) Linbaugh, I’m going to save the recoil lug as a souvenir
7) Right now, it’s the standard option on Brux barrels from me. Pac-Nor and McGowen on request for the moment.

Read more: dougsmessageboards.proboards.com/thread/17077/arrowhead-plug?page=2#ixzz3TtWRXrVH

[rambler]

Hmmmmm very interesting

[jims]

Thanks for sharing.

[Deleted]

You might want to consider a maximized recoil lug if you intend to hunt with that 4000fps load thanks for doing the proof testing Luke and those primers look great! I'll take 20 plugs!

[kash913]

Luke looks like you have something good going. Sounds like is Myers is going to buy your first lot! He is kind of greedy. LOL

[fishhawk]

Well done Luke! That may be a world record speed for the XTP!

[Dave W]

Looks like the 209 can take quite a beating in the right plug.
Earnhardt was pushing pushing large doses slow powder I assume with this plug?
The lack of gas cutting to the threads of the barrel and plug in the 3600+ shot barrel Cole sectioned leads me to believe you will be successful in overcoming that problem. SMIs plug does not have that small snout though.

Price and availability?

Cool video and testing, thanks for aother option for builds!

[ratsnakeboogy]

These are going to sweet for the break opens!

I'm going to need several.

Price and availability estimate?

[edge]

Wow, really cool testing!

Have you been able to remove the BP? If so a look at the threads would be interesting to see how many were distorted.
If you have an interest I could magnaflux the barrel. Cracks may or may not show how close to failure you were.

edge.

[elkman1310]

Great job on the plug design. It couldn't have come at a better time. Because this is the size plug I would need to use in the action I want Lawton to build. Keep up the good work!

[dave d.]

Great looking plug Luke. Looks like a winner

[TGinPA]

Wow! Many thanks Luke. IMO, from a number of perspectives, there is a lot of information gained from this real time testing. It is a big step forward and (IMO)something we really needed. I can only imagine what traces of those loads would show...
TG

[Mid_Tn_Plowboy]

Great testing Luke! Plug looks good.

[Deleted]

yes no doubt this is a much better design than the Savage plug we have been using. we have reached and surpassed the design limitations of the Savage plug with the high end sabotless loads we have been shooting for the last few years. rear sealing is the only way to go, there is no where for the gas to escape, it never makes it past the first couple of threads on the plug vs the savage design where you only have a very thin sealing surface to escape into a unthreaded area for the gases to swirl around in.

And by the way, IT WORKS...

[Richard]

Luke..................I am impressed with the plug and your testing is what makes this board the place to be for smokeless muzzle loaders. Well done!
Richard

[cowhunter]

Fantastic job of designing, testing, reporting, and generally entertaining. Questions. 1. Is the one set of normal test range numbers you gave the only test numbers so far. -- the 70 gr 4198 300 gr bullet at 2700fps? 2. Will this plug come close to stopping primer damage issues, and if so why is that? 3. Explain a bit more about this "rear sealing" concept, and why it is superior 4. Is the powder closer to the primer and is ignition better with this plug? In other words, will loads that have very little loading pressure still tend to ignite better than with the Savage plug?

[Deleted]

Another great feature... That plug won't come loose like the savage style tends to with clean threads. Rear seal will allow the threads to engage the way they are intended to when the plug is torqued in. Great plug Luke!

[Deleted]

Mar 8, 2015 12:23:37 GMT -5 cowhunter said:

Fantastic job of designing, testing, reporting, and generally entertaining. Questions. 1. Is the one numbers you gave the only test numbers so far. -- the 70 gr 4198 300 gr bullet at 2700fps? 2. Does this plug essentially end primer damage issues, and if so why is that? 3. Explain a bit more about this "rear sealing" concept, and why it is superior 4. Is the powder closer to the primer and is ignition better with this plug? In other words, will loads that have very little loading pressure still ignite?

Yes this is awesome!!

I have the same questions and also wonder if you can shoot single powders instead of a with a booster with 100% ignition?

Great job to all that designed this plug!!

[mrbuck]

Really interesting plug design . Those proof loads were something !
Chris

[Deleted]

78riverrat, any shooting I've done with a .040 bushing and singles has looked really good as long as the powder fits the bullet weight you're shooting. Others that have been testing this look to be having the same luck.

[Deleted]

with a rear seal the threads are taking the brunt of the pressure GREATLY reducing the amount the rear seal actually sees. but since there is no place for the gas to escape there is no flow into the threads to speak of..

on the Savage plug you have this very small sealing surface with no threads to reduce the pressure effects and an open area behind this sealing surface for gas to escape into. getting a complete seal on the Savage plug is a feat in and of itself. not bashing the Savage plug but with pressures well past the 40s it shows it weaknesses.

the flame path is essentially the same unless I am mistaken,(I haven't actually measured it yet)but ignition should be essentially the same as the Savage plug..

[linebaugh]

Very, very nice. Far superior product so congrats on that.

A couple quick comments on this. If you eliminate back flow you should have very little to no gas cutting.

On the design you have there you could probably add an o-ring grove to the back and add an o-ring for 1000% seal. Of course if you are not getting any back flow now that idea is worthless.

With the amount of threads you probably have nearly no back flow with or without a seal. Just an awesome looking plug and excellent design ideas.

You should have set up a 3/4" mild steel plate down range for that last shot. A 3/4 plate with a muzzleloader hole burned through would be a neat keepsake. Lol.

[edge]

IMO, you have loose front threads on a plug such as this versus the Savage plug in which the front threads are under tension and the rear threads are loose.

Does it matter? Probably not but a rear seal is easier to insure engagement.
Probably most leaking BP's result from incorrect boring / relieved BP threads near the snout.

edge.

[1gifford]

Great job Luke and Company!!!! I love the pioneering spirit!

[gar]

will these be available for Rem builds and Savage builds? And great job by the way.

[12ptdroptine]

Than, You Luke. Your efforts are greatly appreciated
Drop

[dannoboone]

CHALLENGE: Come up with a heli-coil kit for the 11/16"
tapped barrels.

You just may have come up with the ultimate 209 BP
design. Every thing about it makes perfect sense.
Congratulations!

[12ptdroptine]

Who else has experience in the testing of these ?
Drop

[Richard]

A wrap or two of yellow teflon tape and the ultimate gas seal. Since I have been using the yellow teflon tape on the standard Savage plugs? I get no gas leaking past the threads. I just looked inside my PN barrel which has been removed and as I look at the seat (that engages the plug shoulder) I can see about a 1/3 of it is shinny as there is good contact. The remainder is black, which would indicate some leakage. But, nothing is getting past the threads or destroying the teflon tape seal. FWIW!................Luke's plug looks like the "cats meow!" But don't sell the Savage plug short as it does work.
Richard

[Deleted]

Another question, if we wanted to change to this plug can we have the barrel re threaded to accept this plug, so we can do away with the savage plug if we choose too?