Primers backing out

[Kid Ray]

I have Three Cut built short stroke Ruger pistols that I have shot 3 grains of clean shot for years, all of a sudden one Ruger starts having the primers back out and lock the gun up.  I have 5 other Rugers that shoot the rounds just fine, only issue is this one.  Headspace measure .063 with feeler gauge.  I have increased the load to 3.3 grains of clean shot and problem goes away but the wife does not like the increased recoil, slight as it is.  Any ideas?

[Edward R S Canby, SASS#59971]

What weight bullets are you loading?

[Uriah, SASS # 53822]

Lack of pressure?

[Larsen E. Pettifogger, SASS #32933]

Primers backing out is usually a sign of insufficient pressure.  Why that one gun?  Chambers could be slightly larger, cylinder gap could be wider, etc.  Guns are machines they differ.    If this just started make sure you did not mix the cylinders up between guns.

[The Original Lumpy Gritz]

Fly-fart level load. Add more powder.

[Kid Ray]

bullets are 105's.  Yes problem went away with more powder, but the wife likes the 3 grain loads and I don't understand why it just started on the one gun after years.  Cylinder is the correct one.

 

Edited April 5 by Kid Ray

[Von Dutch, SASS # 7995]

2 minutes ago, Kid Ray said:

bullets are 105's.  Yes problem went away with more powder, but the wife likes the 3 grain loads and I don't understand why it just started on the one gun after years.  Cylinder is the correct one.

 

Powders can very between batches!

[Larsen E. Pettifogger, SASS #32933]

Have you chrono'd these loads?  If they don't have enough energy to reseat the primers when fired chances are they don't meet power factor either.

[Cypress Sun]

New brass?

[Kid Ray]

Used brass.  670 fps.

[Go West]

Either let the wife use pistols that work with that load or try 3.1 or then 3.2 gr. to see if the problem gun stops backing out primers.

[J.D. Daily]

What brand of primers do you use?  I had the problem with Remington 209 primers jamming a Ruger Vaquero cylinder firing CFD wax bullet cartridges.  The primers are slip fit.  The cup bulges when fired and the chamber pressure forces the primer & case head into the recoil shield to flatten the bulge.  Remington primer cups are very soft so they bulge enough that the chamber pressure doesn't flatten the bulge.  The CFD folks told me to use Rio or Winchester primers.

[Kid Ray]

They are Federal primers.  Used for years, this load since 2016.

[Von Dutch, SASS # 7995]

21 minutes ago, Kid Ray said:

They are Federal primers.  Used for years, this load since 2016.

Well Federal primers are not the quality they once were!

[Cheyenne Ranger, 48747L]

trade guns with the wife

[Leroy Luck]

You mention that it’s used brass… as unlikely as it is, it could be loose primer pockets. 
 

How many times/often does it happen? 

[Eyesa Horg]

Seems to be a gun issue to me. The OP stated he has 5 other Rugers that have no issue, only this one and his ammo is the same he's been using for ten years. Doesn't strike me as an ammo issue. 

[Kid Ray]

I agree, hoping for some gun issues here!

 

it happens about every 10-15 rounds with the one gun only.

 

[TN Mongo, SASS #61450]

All good possible explanations listed above. In the past, I've had problems with primers backing out due to loose primers pockets (as previously mentioned) in older used brass.

 

I would defer to more knowledgeable cowboys on this, but wouldn't seating depth and tightness of crimp all affect pressure?

Edited April 5 by TN Mongo, SASS #61450

[Tex Jones, SASS 2263]

I don't know it it applies to Rugers, but I have a USFA SAA that had the firing pin bushing come loose, which caused the fired primers to back out and lock up the cylinder.  From what I just read, Rugers have a bushing that they call a recoil shield and it may be that this part has come loose.  Good luck.

 

 

[The Original Lumpy Gritz]

1 hour ago, Kid Ray said:

I agree, hoping for some gun issues here!

 

it happens about every 10-15 rounds with the one gun only.

 

Have you calibrated your scale?

New lot of powder?

Do you use a firm roll-crimp? 

[watab kid]

10 hours ago, Go West said:

Either let the wife use pistols that work with that load or try 3.1 or then 3.2 gr. to see if the problem gun stops backing out primers.

dittos this , you need the primers to reset , what caliber are we talking about ??

[Abilene, SASS # 27489]

8 hours ago, Tex Jones, SASS 2263 said:

I don't know it it applies to Rugers, but I have a USFA SAA that had the firing pin bushing come loose, which caused the fired primers to back out and lock up the cylinder.  From what I just read, Rugers have a bushing that they call a recoil shield and it may be that this part has come loose.  Good luck.

 

 

I was going to mention this but saw Tex did.  I haven't heard of the firing pin bushing getting recessed in Rugers, but maybe?  Pretty easy to check.  Look to see it doesn't have a little dimple developing around the firing pin hole in that bushing as well.  Good luck.  

[Kid Ray]

They are 38's.  Good idea to calibrate scale!  New and old lot of powder.  Yes, firm roll crimp.  

[The Original Lumpy Gritz]

1 hour ago, Kid Ray said:

They are 38's.  Good idea to calibrate scale!  New and old lot of powder.  Yes, firm roll crimp.  

Take your calipers and measure the chamber diameter of the problem gun and compare it to the other guns.

Up the powder charge to 3.2gn.

Calibrate your scale before every reloading session 

Edited April 6 by The Original Lumpy Gritz

["Big Boston"]

 

You may not like my answer, which is a theory I tested to either prove or dismiss. 

 

As already stated the issue is one of pressure. Pressure and velocity are linked. It stands to reason the as you load less powder to lower the velocity, the pressure is lowered as well. How does that relate to your primers backing out? 

 

As the hammer falls, the first thing that happens is the case is driven into the chamber by the firing pin. The firing pin dents the primer and it explodes, creating pressure in the primer pocket. This pressure is throttled or restricted by the flash hole. In my experiment I did not load a bullet or powder, just a primer. What happened, the pressure built up in the primer pocket was sufficient to push the primer back and lock up the cylinder. I could have tried a heavier hammer spring to determine if a heavier hammer spring would help, but even if that were the solution, it's not something I wanted. 

 

The only other way to relieve the pressure would be to enlarge the flash hole. I did this in steps, until the primer did not back out. In my brass, with the primers I was using, that occurred at .100". That is still within safety limits, but with some powders at  certain volumes, ignition issues may occur. But, the object was to prove that the pressure built up in the primer pocket was backing out the primer.

 

If you load a case with only a primer and it backs out, you can assume or deduce that the primer will always back out, and the only thing that can pusk it back in is the pressure inside the powder chamber must then be sufficient to push the case back against the frame of the revolver with enough force to push the primer back in. The force pushing the firing pin is a factor, how much of a factor, I don't know. I never tested that.

 

Reduced, low velocity/pressure loads exist in that grey area of ballistics. The norm is to be at or slightly below maximum rated pressure. There is not minimum rated pressure specification for cartridges.

 

But there is a powder, Trail Boss, that is low energy but has elevated pressure. That is why reloaders using Trail Boss have fewer issues of this type. 

 

Obviously, if you were to enlarge the flash hole, you would solve your issue. I completed my experiment and then destroyed that brass. Not because I believe it is unsafe, but because the logistics of keeping track of the modified cases may be a problem. I did not experiment with high power or full pressure loads, but it stands to reason that that same flash hole is a orifice or pressure valve in both directions. It also limits the amount of chamber pressure that could also push against the primer.

 

BB

[Marauder SASS #13056]

20 hours ago, Kid Ray said:

They are Federal primers.  Used for years, this load since 2016.

That's the problem, Kid.  I only use primers once each....   

[Marauder SASS #13056]

Very interesting!
Is the problem only in one cylinder?
How does the headspace on that revolver compare to your others?
Compare the measurements of the front and back cylinder spaces with your other guns.

You might try lightly polishing the cylinder to better allow the brass to move and see if that helps.
We know that the pressure is not high enough in those cylinders to overcome friction and allow the brass to slam into the frame adequately.

[Rye Miles #13621]

Just use the 3.3 and take your wife to dinner, maybe flowers or candy? 🤣🤣🤣🤣

[Assassin]

If the front of the cylinder is worn, where it rubs the frame,  it could be moving forward not allowing the primers to reseat fully against the recoil shield. 

[Rooster Ron Wayne]

Too light of a powder charge

[Scarlett]

On 4/5/2026 at 3:22 PM, Cheyenne Ranger, 48747L said:

trade guns with the wife

Obviously, you don’t know Sue Render! @Kid Ray is truly in a hard spot! 😂🤣😂

 

Hugs!

Scarlett

[Griff]

You mentioned that you have .063" of head space... are you referring to the cyl/bbl gap?  What about endshake?  Do fired rounds drop out of all the chambers, or does one or more tend to stick?  With constant use of light loads, you may have some carbon fouling near the mouth of the case, causing cases to stick.

[Jackaroo, # 29989]

On 4/6/2026 at 1:56 AM, Kid Ray said:

bullets are 105's.  Yes problem went away with more powder, but the wife likes the 3 grain loads and I don't understand why it just started on the one gun after years.  Cylinder is the correct one.

 

If only 3 grains change the bullet to a 125 grain, and don't ell your wife. If the primers dont back out, then you're good to go, she'll never notice the difference.

[Arcadia Outlaw, SASS 71385]

3 hours ago, Jackaroo, # 29989 said:

If only 3 grains change the bullet to a 125 grain, and don't ell your wife. If the primers dont back out, then you're good to go, she'll never notice the difference.

Totally agree. In my experience a heavier bullet going slower feels better (less felt recoil)than a lighter bullet going faster. In fact I just recently tried a 105 gr bullet where I had been using a 125 gr and the load was too light and had primer issues.

 

AO