Reloading-Loctite on Primer Pockets?

[Slamfire]

Primers "will" back out with under presser loads or with a simple primer, but only if there is enough excess headspace to allow the primer to move.

If the case head is tight to the bolt face there is no where for the primer to go, if there is a "space" then it will back out.

I have not tested that, but regardless, except for my 35 Whelen, I set the shoulder back about 0.003" from the chamber, or, as in the ammunition for my AR15's, M1a's, and Garands, I set the shoulder back to cartridge headspace gage minimum. I have had a lot fewer function issues adding some clearance between the cartridge headspace and the chamber headspace. And for ammunition used between several rifles, I will size to gage minimum.

My 35 Whelen, it has such a slight shoulder that sizing the case so chamber dimensions and using the most sensitive primer I could find, I stopped having misfires. The shoulder on a 35 Whelen is so slight that the firing pin blow appears to resize the thing, at least, it cushions the firing pin blow.

 

[Jesse Heywood]

The only application that I am aware of where Loctite is used is when substituting large rifle primers for Berdan primers, where the pockets are too large and the primers are loose. In that case, some have had success with red Loctite allowing the sealer to cure 48 hours.

 

[Walkalong]

As steve4102 pointed out, there must be some head clearance for the primer to back out, and since we almost always do, the primer backs out a bit. Some people like to size cases to a jam fit, with zero head clearance, but IMHO that is a bad way to load ammo.

So, the firing pin hits the primer, pushing the case forward against the shoulder (Or Belt), the round fires, the primer backs out, and the front portion of the case expands, grabbing the chamber walls, then the rest of the case slides backwards, stretching in the middle, usually where the thick rear transitions to the thinner front, until it hits the breech, re-seating the primer. Light loads don't have enough pressure to stretch the case and so the primer doesn't get re-seated.

When we have too much head clearance, whether because of a mechanical headspace problem with the rifle or improper sizing moving the shoulder too far back, we can stretch the case so much we get a case separation. Sometimes on the first firing, and sometimes on the second or third.

 

[Bart B.]

In my tests with primed new Federal .308 Win cases, the nickel plated ones' shoulders set back about .006" from firing pin impact. Brass ones about .003". That's with a Win 70 classic with a new 24-pound spring on the firing pin and the pin tip protrudes .060" past the bolt face when full forward in the bolt.

Loading those same lots of new cases with 44 grains of IMR4064 over Federal 210 primers and under Sierra 165-gr. SBT bullets, fired case headspace was .002" to .003" greater than when new; case length shortened a few thousandths. Full length sizing setting shoulders back .002" made case length grow almost .001" each time for each case. They were reloaded with the same stuff but 1 grain less powder incrementally to 38 grains or so. Full length sizing these cases returned case headspace to about 1.630" but case length grew almost .001" each cycle.

At 40 grains of powder, some of the primers were backed out a thousandth or two past the case head, case headspace was about the same as before firing.

Each grain below 40, case headspace got a couple thousandths shorter, primers were backed out a couple thousandths more. At 38 grains, primers were backed out about .007" and case headspace was about the same amount shorter than when new.

From which I surmised that powder charges for rimless bottleneck cases shouldn't be more than about 10% under max because cases will end up with less headspace than before they are fired. This can lead to head separation.

Some people think all cases in rifles are held against the bolt face by the extractor. There's several thousandths clearance between bolt face and extractor hook to ensure loaded round's rim will easily go between the extractor. And extractor clearance to the bolt face is not so long that cases at minimum headspace won't stop against the extractor claw but instead stop against the chamber headspace point. Measure the clearance on your own rifles then compare that to their cartridge's rim thickness.

 

[Rule3]

So the method for removing Re Locktite is by heating it.

How hot does a piece of brass get at the primer when ignited??

This reminds me of Seinfeld episode.

http://www.loctiteproducts.com/p/t_lkr_red/directions/Loctite-Threadlocker-Red-271.htm

Cleanup

Clean adhesive residue immediately with a damp cloth. Cured product can be removed with a combination of soaking in methylene chloride and mechanical abrasion such as a wire brush.

For disassembly, heat parts up to 482°F (250°C) and separate parts while hot.

 

[Jesse Heywood]

So the method for removing Re Locktite is by heating it.

How hot does a piece of brass get at the primer when ignited??

This reminds me of Seinfeld episode.

http://www.loctiteproducts.com/p/t_lkr_red/directions/Loctite-Threadlocker-Red-271.htm

Cleanup

Clean adhesive residue immediately with a damp cloth. Cured product can be removed with a combination of soaking in methylene chloride and mechanical abrasion such as a wire brush.

For disassembly, heat parts up to 482°F (250°C) and separate parts while hot.

I think the heat & pressure break the bond. Never was desperate enough to try. Looks like if you wanted to remove a live primer heat would be your best friend and your worst enemy. Place the case in a vise, stand to the side and heat the primer. If all goes well the primer will hit the wall. If not you might these new glasses

 

[murf]

primers fired in empty cases (no bullet or powder) won't back out because there is nothing to contain the explosion; the blast goes out the flash hole and down the barrel. now try that with a bullet pressed into the sized case, and all bets are off. if the pressure generated by the primer explosion being contained in the case is sufficient to overcome the friction between the primer cup wall and the case wall, the primer will back out; if not, it won't.

murf

 

[steve4102]

primers fired in empty cases (no bullet or powder) won't back out because there is nothing to contain the explosion; the blast goes out the flash hole and down the barrel. now try that with a bullet pressed into the sized case, and all bets are off. if the pressure generated by the primer explosion being contained in the case is sufficient to overcome the friction between the primer cup wall and the case wall, the primer will back out; if not, it won't.

Nope, and as you put it "going out the flash hole" is what backs out the primer.

How does it go, "with every action there is an equal and opposite reaction."

 

[murf]

steve4102,

how much affect does the weight of the firing pin (and spring) pushing on the primer (during the primer explosion) have on keeping the primer fully seated in the case? wouldn't the much greater mass of the pin keep the "equal and opposite" reaction from happening?

murf

 

[Bart B.]

I once had to shoot 42 rounds of 7.62 NATO reloads (new M118 cases and primers) to get 2 sighters and 20 record shots down range in a 1000-yard match. Seems the shop that reloaded them left out 44 grains of IMR4320 under the Sierra 190 HPMKs in some rounds.

None of those without powder had primers backed out; they were at original seating depth below flush with case head. None pushed bullets into the rifling, either. Fired cases had primers flush and flattened level with case head.

I sorted the "clickers" from the "bangers" by weighing the remaining 18 rounds of the 3rd box of ammo; some weighed 44 grains less than the others and pulling a few of their bullets revealed no powder inside.

 

[higgite]

So a buddy of me who I consider to be pretty knowledgeable in the firearms field informed me that if I'm loading 5.56 NATO, I should be using red loctite to lock in my primers. This doesn't seem right to me.

His claim is that the higher pressures in the 5.56 NATO Cartridge will cause the primers to back out due to the increased pressure and loctite will prevent this.

Is this accurate at all?

With friends like that, you don’t need enemies.

Red Loctite “cures in the absence of air between close fitting metal surfaces”, to quote Loctite. So, unless you apply it in the primer pocket before seating the primer, or apply it to the wall of the primer cup before you seat the primer, you might as well use red nail polish.

Another drawback would be having to heat the brass to 500 deg F to get the spent primer out. I'm thinking that sliding a case into the shellholder would be pretty cumbersome with oven mitts.

 

[GaryL]

Primers are factory sealed with a lacquer based sealant that is essentially thinned nail polish. It is designed to wick into the gap. And a little goes a long way. That is not to say other sealants haven't been tried or used.

I also know that walking by a cubic yard of freshly minted ammo waiting for packaging creates a strong urge to back up the truck.

So the method for removing Re Locktite is by heating it.

How hot does a piece of brass get at the primer when ignited??

A good question. I know it can get hot enough to boil water, but not for long.

Something to consider though, thermal transfer is not an instantaneous process. Also, if the primer cup is heating up relative to the surrounding brass, it will expand and increase the fit tension. But that won't last long either.

Its easy to not think about processes that only last a few milliseconds, or less.

 

[73ch13]

With friends like that, you don’t need enemies.

Red Loctite “cures in the absence of air between close fitting metal surfaces”, to quote Loctite. So, unless you apply it in the primer pocket before seating the primer, or apply it to the wall of the primer cup before you seat the primer, you might as well use red nail polish.

Another drawback would be having to heat the brass to 500 deg F to get the spent primer out. I'm thinking that sliding a case into the shellholder would be pretty cumbersome with oven mitts.

He actually did say I should apply the loctite to the edges of the primers before I seat them...

(Facepalm)

-Safety is no accident, unless you accidentally leave the safety on when you intend to shoot.

 

[Walkalong]

Nope, and as you put it "going out the flash hole" is what backs out the primer.

How does it go, "with every action there is an equal and opposite reaction."

With no bullet or powder there will be no pressure, so the front of the case won't grip the chamber walls, the primer explosion will exit the case mouth and push the case back and re-seat the primer, it it ever backed out in the first place.

At least that is my take. Anyone want to try it?

And as I found out yesterday, a loose primer can end up dang near anywhere.

 

[MEHavey]

Anyone want to try it?

Been there
Done that.

Try it with any revolver case and the primers ALL bind up/back out against the shield face -- and stay there.

Don't forget the flash hole is relatively small and effectively turns itself into a primer rocket nozzle -- with the primer going the opposite direction.

 

[PegLegPeat]

Nosler for example lists both 223 and 5.56 data.

If you read the technical specs/info on their data you will find that they seperated their data based on twist rate and bullet weight, Not on pressure.

They say their data for both the 223 and 5.56 are safe to load in either chamber, i.e. Same pressures.

I suspect Hornady does the same, but I do not have a #9 to verify.

A quick look at my Hornady #9 does show slightly higher max charges for 5.55 vs .223 with the same bullet/ powder. Not sure if that helps, but there it is.

It also says the 5.56 data should only be used in rifles chambered in 5.56. But that could have more to do with listing longer OALs

 

[Walkalong]

Don't forget the flash hole is relatively small and effectively turns itself into a primer rocket nozzle -- with the primer going the opposite direction

Makes sense, and rings a bell.

 

[hdwhit]

So a buddy ... informed me that if I'm loading 5.56 NATO, I should be using red loctite to lock in my primers.

Let's assume that he's not playing with you. If so, it seems likely he has seen the sealant put on many military cartridges and assumed what it was and its function. As Walkalong already mentioned, it is not Loctite but a sealant to keep contaminants from fouling the primer or powder. To be effective, you would need to seal both the primer and the inside of the case neck. It is not necessary for handloaded ammunition.

I DO seal my primers, but it is for cosmetic reasons. I use fingernail polish. It works well and it is much cheaper than the dedicated sealants the gun stores sell. Simply brush some on the primer and then quickly wipe off with a paper towel. I generally do five primers at a time before I start wiping otherwise the polish will start to set up. I have no problem with the polish "flaking" off or contaminating my firing pin, bolt or action. I do occasionally get a colored ring on the face of the bolt, but a Q-tip with Hoppe's #9 takes it right off.

 

[P-32]

how much affect does the weight of the firing pin (and spring) pushing on the primer (during the primer explosion) have on keeping the primer fully seated in the case? wouldn't the much greater mass of the pin keep the "equal and opposite" reaction from happening?

getting a little off topic here but try this easy enough to do. Load up a wheel gun with primer only cases and see how long it takes to lock that puppy up....the primers will back out. Not enough pressure to hold them in place during the firing cycle.

 

[Bart B.]

Regarding the comments about firing pin weight and its spring strength, read my post 35.

Note I've shot a few dozen primed rifle cases without powder or bullet testing shoulder setback from pin impact and no primers backed out. Nor did any in rounds without powder but a bullet in them. The inside of the case was blackened from powder residue. Bullets were still held in place; didn't move out of the case at all.

Bolt gun pins and springs put a lot more force on primers than handguns. Both an S&W 19 and Colt Trooper will let primed .38 Spcl cases without powder and bullet ended up with primers backed out.

 

[Rule3]

I think the heat & pressure break the bond. Never was desperate enough to try. Looks like if you wanted to remove a live primer heat would be your best friend and your worst enemy. Place the case in a vise, stand to the side and heat the primer. If all goes well the primer will hit the wall. If not you might these new glasses

I was refering to firing a live round which had the primer "glued in" (for whatever reason) I would think, as you say the heat and pressure would loosen it, so what possible good could it do??

Back to Sienfeld,the epsiode/show about nothing.

 

[Reloadron]

If using a primer or bullet sealant gives anyone a warm fuzzy feeling then have at it using Markron Custom Bullet and Primer Sealer. Personally I see no need for it but whatever trips anyone's trigger. I can pretty much say the red sealant frequently seen on GI ammunition is not loctite red.

Do have a question regarding Slamfire's post and pressure.

but I believe the average pressure is over 60,000 psia with a max probably around 65,000 psia.

Taken from the Wiki:

Pounds per square inch absolute (psia) is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around 14.7 psi, this will be added to any pressure reading made in air at sea level. The converse is pounds per square inch gauge or pounds per square inch gage (psig), indicating that the pressure is relative to atmospheric pressure.

So wouldn't chamber pressure typically be expressed as psig rather than psia? Not that it matters much with a 60,000 psi chamber pressure.

Ron

 

[steve4102]

Note I've shot a few dozen primed rifle cases without powder or bullet testing shoulder setback from pin impact and no primers backed out. Nor did any in rounds without powder but a bullet in them. The inside of the case was blackened from powder residue. Bullets were still held in place; didn't move out of the case at all.

http://yarchive.net/gun/ammo/primer_backing_out.html

From: [email protected] (Bart Bobbitt)
Newsgroups: rec.guns
Subject: Re: Garand question
Date: 14 Apr 1994 13:38:52 -0400

Don Baldwin ([email protected]) wrote:

: On some of the
: cases, the primers looked like they had backed out the teeniest bit. And
: the bottoms of the cases looked very slightly bulged, about 1/4 inch back
: from the head.

This is a very normal occurance when peak pressure is far below the
normal, maximum amount. What happens is the case is pushed forward by
the firing pin as the primer is struck. When the case expands to fill
the chamber, the lower-than-normal pressure isn't enough to push the
back of the case fully against the bolt face. But the primer isn't
held in place with much tension, so it gets pushed back against the
bolt face. Max pressure cartridges push the case head hard against
the bolt face; there's no place for the primer to stick out its pocket
against.

If the new brass has smaller than normal diameters just in front of the
extractor groove, it will bulge out to a much greater diameter than the
case has; another normal thing even with maximum loads.

FMJ bullets have about the same jacket hardness as hunting bullets, so
I doubt if this is the cause. If you barrel's groove diameter is on
the large size, some factory ammo won't generate normal operating pressure
and that may be the cause of the primer's backing out.

BB

From: [email protected] (Bart Bobbitt)
Subject: Re: Mauser questions
Organization: Hewlett-Packard Fort Collins Site

Marc Cassidy ([email protected]) wrote:

: One thing I've noticed is that the thing is starting to
: push the primers out of the pocket just a tiny bit (slightly
: more than flush with the cartridge base). I realize that
: this is the beginning of head space problems. My big
: question, is it time to stop shooting the gun?

I doubt if the rifle's headspace is the problem. It may be one of these.

If you are shooting reloaded ammunition, the powder charge may not be
enough, either by design or by accident. When the firing
pin forces the cartridge fully forward in the chamber as it detonates
the primer, the case expands. But it doesn't expand enough because of
lower than normal pressures. The case side walls grab the chamber walls
but the head of the case doesn't go all the way back against the bolt
face.

The other problem may be that you are setting the shoulder back too much
if you're full length resizing the cases. This lets the case go too far
in the chamber and can cause the same situation as noted above.

The last possibility is the barrel is very worn out. Not enough pressure
is generated and causes the above situation to happen; even with normal
new factory ammo.

A competant gunsmith should inspect the rifle and your ammo. It's easy
to determine what is causing the problem once the rifle and ammo is
correctly evaluated.

BB


From: [email protected] (Bart Bobbitt)
Subject: Re: Load pressure question...
Organization: Hewlett-Packard Fort Collins Site

Minh Lang ([email protected]) wrote:

: I would appreciate any comments to the following:

: - Definitely there was high pressure as the primers were backed out?

I don't think you had enough pressure; it was too low. With high
pressure, the case head would have been forced against the breech
face and the primer would only have gone back just as far. The primer
would be flush with the case head.

: - What caused the bulge in 180 degree near the case head? Not the
: headspace, I believe, since the brass I used were once-fired from
: new by myself in the same gun&barrel and they were neck sized
: after the first firing.

One side of the case was thinner than the other. That's probablly the
side that bulged out. This is a very normal thing.

: - This high pressure symptom developed at 2.5g under the suggested
: maximum load was due to my *long* OAL? (only 0.005" off-the-land)

Again, you had too low a pressure, not too high.

: - Should I trash all these brass even thought I found no thinning of
: any kind? Or can I full-length resize them and reload again, since they
: are only twice-fired now? If I can, should I FL resize and not pushing
: the shoulder back? (I have FL resized one of these cases by
: not touching the shoulder - back off the die half-turn
: from where it touches the shell holder - and the round was chambered
: easily)

Full-length size those cases, but don't set the shoulder back more than
one or two thousandths of an inch from where they headspace as fired.
Your brass will last much longer and typically be more accurate this way.

BB

 

[murf]

bart b.,

thx for the extra info on pistol primers backing out. i'd much rather cock the hammer on any revolver than engage the safety on a mosin nagant!

murf

this thread also gave me an idea on why we disagreed on case shoulder setback with primer only in a bolt gun. my test was to hit an already fired primer with a punch and hammer to see if the case shoulder would set back. it didn't and i said i didn't believe your results. well, i didn't use a live primer and that skewed the results. i forgot that the primer is a big ol' hammer in this scenario and gives the case a good shove forward when it goes off.

i changed my mind and can now see how a "primer only" round can set back the case shoulder. my apologies, bart.

 

[Bart B.]

Murf,

I've put dead primers in empty cases then fired them in rifles. Case shoulders set back the same amount as if the primer was a live one. I had one dead primer in a .308 Win case full of powder and a bullet seated; it also had its shoulder set back about .003" and the primer had an extra deep dimple from pin impact but nothing burned the powder.

You probably didn't smack the punch hard enough in your tests if case shoulders didn't set back. Firing pin springs in modern rifles have about a 25-pound load force on the firing pins.