Author Topic: should breech plug be water tight (Read 6471 times)

Gary Rad · « **on:** December 31, 2018, 03:36:46 AM »

Hi, I today I was cleaning a gun I just recently built and noticed the breech plug is not water tight. Is this a problem and if so how do I correct it.
Thanks Gary

Acer Saccharum · « **Reply #1 on:** December 31, 2018, 04:23:20 AM »

First of all you must be sure you have enough thread engagement. With the plug backed out a turn, does it rattle around, or is the fit snug between plug and barrel?

If snug:
If the barrel was drilled out too big before tapping, the crests of the plug threads could feel snug in the barrel, while leaving a sizeable gap between plug and barrel at the root of the plug threads. When you look at the barrel threads, you might see the crests are very flat.

If loose:
1) and the plug is undersized: fit a new plug with larger threads

rfd · « **Reply #2 on:** December 31, 2018, 03:19:56 PM »

not at all good.

as mentioned above, a breech plug must be *Tight* and should be properly greased.

get that looked at by a pro.

Mikecooper · « **Reply #3 on:** December 31, 2018, 04:13:03 PM »

greased?

rfd · « **Reply #4 on:** December 31, 2018, 04:23:46 PM »

"threads anti-seize lubed"

Craig Wilcox · « **Reply #5 on:** December 31, 2018, 04:26:55 PM »

Mike, the plug needs some anti-seize on the threads. I use Locktite's, which is copper based. This helps to ensure that the male threads don't seize into the female threads, so that the plug can be removed if necessary.

As the plug should be gas tight, I would assume that it should also be water tight.

Hope we have been able to help you. If that plug is loose, get someone with experience to fit a new, tight one. Not an easy job, takes some finicking around, but not terribly difficult either,

Long John · « **Reply #6 on:** December 31, 2018, 04:40:20 PM »

Gary,

My short answer is YES.

The ideal breech plug will form a seal between the breech plug face and the ledge at the bottom of the female threaded hole for the plug. If the threads are properly sized (see Acer's post) then the plug won't blow out but generally straight screw threads don't result in a sealing joint, they result in sufficient force to cause a seal at the breech plug face; unless, the breech plug face wasn't properly finished.

I generally use Lock-tite 242 to seal threads after making sure I have a proper seal at the breech plug face.

JMC
John Cholin

rfd · « **Reply #7 on:** December 31, 2018, 04:45:16 PM »

it pays to use a proper anti-seize grease. this will allow two things - seal the threads from bp residue mitigation and allow future removal of the plug. the best anti-seize lube i've found to date is Nikal, and it's rated above 2600*F. using this grease, i've pulled breech plugs that were over two years old, after many firings. and they were all easy extracts and no signs of thread compromise.

smylee grouch · « **Reply #8 on:** January 01, 2019, 12:27:05 AM »

Also, if it is at all not tight enough to seal out water it probably will retain water when cleaning and rust that much sooner. Not good.

Gary Rad · « **Reply #9 on:** January 01, 2019, 02:53:55 AM »

Thanks for all the info I will take it apart and see where the problem is.
Thanks again Gary

Gary Rad · « **Reply #10 on:** January 01, 2019, 02:59:42 AM »

What does everyone think about a high density Teflon tape let me know
Thanks,Gary

stikshooter · « **Reply #11 on:** January 01, 2019, 03:18:54 AM »

Teflon tape is great for plumbing as noted , use anti seize for breech plugs/and other parts on your gun that you might want to change out/remove/it"s a good practice /Ed

galudwig · « **Reply #12 on:** January 01, 2019, 03:20:20 AM »

Quote from: Gary Rad on January 01, 2019, 02:59:42 AM

What does everyone think about a high density Teflon tape let me know
Thanks,Gary

Uh, NO. PLEASE get the barrel into the hands of someone who can breech it properly for you.

P.W.Berkuta · « **Reply #13 on:** January 01, 2019, 07:33:59 PM »

Quote from: Gary Rad on January 01, 2019, 02:59:42 AM

What does everyone think about a high density Teflon tape let me know
Thanks,Gary

Depending on the fit between the plug & barrel threads : if the plug is so loose that it wiggles around when backed out 1/2 turn you will need to replace the plug. If it is just a bit snug while the plug is being backed out I WOULD use Teflon pipe tape on the plug's threads and thread it back in then pour some water in the barrel and see what happens. The Teflon tape might just do the trick and will also allow you to be able to remove the plug if needed - my two cents worth

.

Turtle · « **Reply #14 on:** January 01, 2019, 10:52:54 PM »

I have used blue(low strength) locktite on breech plugs and vent liners for over 20 years. Seals great and they come right out if you need to remove them. the threads are perfect looking after removal. I became sold on anaerobic sealers as a mechanic.

Mr. Bubbles · « **Reply #15 on:** January 03, 2019, 12:30:37 AM »

If it won't hold in / out water at only 1-2 psi how can you expect it to be sealed from gas pressure at 10,000-15,000?

Robby · « **Reply #16 on:** January 03, 2019, 04:15:11 PM »

I have done smooth bore barrels with a hook breech where the face of the bore is virtually nonexistent. 16 ga. for example the bore is .662, the major pitch diameter for 3/4-16 plug typically used is .750, the minor is .671(max.). It still requires proper timing to have the plug vertical but there is no real face to mash against. Through filing and trying repeatedly I get the plug vertical and the lead thread to mash into the last remaining thread but would it be water tight? I don't know, I never tried it. I do wrap the thread with teflon plumbers tape upon the final insertion though so I suspect it is. I have no problem with this, my own fowler has been done this way and has taken many turkeys and broken countless clay pigeons and missed countless more, without a problem.
Robby

Gary Rad · « **Reply #17 on:** January 04, 2019, 02:50:12 AM »

Just to let everyone know the breech plug fits very good and tight I am just not getting a good seal on the face of the plug. I am going to work on it this winter and see what I can do with it.
Thanks, Gary

mikeyfirelock · « **Reply #18 on:** January 04, 2019, 06:11:08 AM »

I have always fitted breechplugs with a file, not having access to a lathe or other sophisticated equipment. It can be done, since it was done this way in the olden days, and was perfectly satisfactory. Attached find some pics of the patent breech I fitted to my next project. This was a barrel I bought from one of our members here and the original breechplug was not available. The pictures show the breechplug,after some filing to length according to measurements of both the hole and plug, and threaded by hand to the point where it could not be tightened further, then fully tightened (using a crescent wrench for that last little bit. Lastly is a front view of the plug with transfer agent (inletting black) showing that there is contact the full circumference of the plug. Since the plug was hand filed, there are black spots around the plug. Hand filing does leave a less than perfect circle, but I would suspect the gaps are probably not much more than the thickness of the layer of inletting black....ie. thousands of an inch.
It’s slow, but I’ve done ”a few “ rifles this way (probably 20 ?) and never had a problem. It does take a lot of time and care to do right.

Turtle · « **Reply #19 on:** January 04, 2019, 02:12:20 PM »

If you think about the way a breech plug is constructed, It is a poor design if it was meant to hold air or fluid pressure -think plumbing or hydraulics without some sort of sealer. The parallel threads themselves can"t seal and fitting the steel knob perfectly to the steel barrel for a perfect seal coinciding with proper timing is real hard. I do it best I can, but I consider it as a seal to keep crud from accumulating there-not a gas tight seal. This is why I seal the threads with blue locktite. Years ago before I knew enough to be concerned, I saw several guns that leaked from the plug when being cleaned, none ever caused a problem, but today I would like to unbreech them and have a look at the threads.

Bob Roller · « **Reply #20 on:** January 04, 2019, 05:01:13 PM »

Quote from: Acer Saccharum on December 31, 2018, 04:23:20 AM

First of all you must be sure you have enough thread engagement. With the plug backed out a turn, does it rattle around, or is the fit snug between plug and barrel?

If snug:
If the barrel was drilled out too big before tapping, the crests of the plug threads could feel snug in the barrel, while leaving a sizeable gap between plug and barrel at the root of the plug threads. When you look at the barrel threads, you might see the crests are very flat.

If loose:
1) and the plug is undersized: fit a new plug with larger threads

I had a repro Harpers Ferry 1803 that was new and unfired several years ago.
Before firing it I removed the breech plug** which almost fell out after one turn
and when I looked thru the barrel I thought I was hallucinating. The 3 groove
rifling started,stopped at the transition between octagon and round and then
restarted.The external transition area was a too deep cut with a parting tool.
I sent this back to the dealer with a recommendation he should examine ALL
these guns he had in inventory.All of these guns were European manufacture.
** The length of the threads was about 3/8 of an inch.
Bob Roller

shortbarrel · « **Reply #21 on:** January 05, 2019, 12:54:59 AM »

I have posted here about this once or twice before. Safety is the main issue. If you don't know how to breech a rifle, find someone who does.

Nhgrants · « **Reply #22 on:** January 05, 2019, 01:34:35 AM »

Is Permatex antisieze ok for a breech plug? I think the container says up to 1600 degrees.

Turtle · « **Reply #23 on:** January 05, 2019, 03:15:31 AM »

Antisieze will allow the plug to come back out, but will not seal the threads. Blue locktite does both.

tallpine · « **Reply #24 on:** January 05, 2019, 06:07:27 AM »

Quote from: Turtle on January 04, 2019, 02:12:20 PM

If you think about the way a breech plug is constructed, It is a poor design if it was meant to hold air or fluid pressure -think plumbing or hydraulics without some sort of sealer. The parallel threads themselves can"t seal and fitting the steel knob perfectly to the steel barrel for a perfect seal coinciding with proper timing is real hard. I do it best I can, but I consider it as a seal to keep crud from accumulating there-not a gas tight seal. This is why I seal the threads with blue locktite. Years ago before I knew enough to be concerned, I saw several guns that leaked from the plug when being cleaned, none ever caused a problem, but today I would like to unbreech them and have a look at the threads.

This is an interesting thread. Turtle , you make an excellent point. I read somewhere that old time gunsmiths used Pine pitch to seal breech plugs.

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Author Topic: should breech plug be water tight (Read 6471 times)

Gary Rad

rfd

Mikecooper

rfd

rfd

Gary Rad

Gary Rad

galudwig

Turtle

Gary Rad

Turtle

Turtle