Moisture in bore between strings

[PepeLp]

I've got a really weird situation. I'm shooting a 6GT, 105 Berger Hybrid, Alpha Brass bumped .002", 33 gr Varget (weighed), Fed 205 Primer. Running 2,926 with an SD of 6.8.

The other day I shot 5 with no issues, then I took a break for a few minutes. The next 2 shots gave heavy bolt lift and ejector marks, but no increase in velocity. I stopped, pulled the bullets in the remaining rounds and the powder charge was fine. Very strange. Loaded up 10 more with 32.5gr Varget. No issues.

The same thing happened the next day. After a couple with pressure signs, no velocity increase, I stopped shooting and checked the bore with a bore scope. The scope was pushing water down the bore. It was soaked.

I'm pretty sure that moisture forming in the bore while it is cooling between strings is causing my pressure issue. I've never experienced this before, or even heard of it happening. Has anyone else experienced this? Any ideas on how to prevent it from happening in the future?

 

[Straightshooter1]

I've got a really weird situation. I'm shooting a 6GT, 105 Berger Hybrid, Alpha Brass bumped .002", 33 gr Varget (weighed), Fed 205 Primer. Running 2,926 with an SD of 6.8.

The other day I shot 5 with no issues, then I took a break for a few minutes. The next 2 shots gave heavy bolt lift and ejector marks, but no increase in velocity. I stopped, pulled the bullets in the remaining rounds and the powder charge was fine. Very strange. Loaded up 10 more with 32.5gr Varget. No issues.

The same thing happened the next day. After a couple with pressure signs, no velocity increase, I stopped shooting and checked the bore with a bore scope. The scope was pushing water down the bore. It was soaked.

I'm pretty sure that moisture forming in the bore while it is cooling between strings is causing my pressure issue. I've never experienced this before, or even heard of it happening. Has anyone else experienced this? Any ideas on how to prevent it from happening in the future?

Hmmm??? Sounds like very humid conditions, which I think can easily result in this???

I would have run a test by stop shooting; let the water accumulate, then run a clean patch down the bore and resume firing to see if that'll work to avoid the heavy bolt and ejector marks.

 

[Webster]

I've got a really weird situation. I'm shooting a 6GT, 105 Berger Hybrid, Alpha Brass bumped .002", 33 gr Varget (weighed), Fed 205 Primer. Running 2,926 with an SD of 6.8.

The other day I shot 5 with no issues, then I took a break for a few minutes. The next 2 shots gave heavy bolt lift and ejector marks, but no increase in velocity. I stopped, pulled the bullets in the remaining rounds and the powder charge was fine. Very strange. Loaded up 10 more with 32.5gr Varget. No issues.

The same thing happened the next day. After a couple with pressure signs, no velocity increase, I stopped shooting and checked the bore with a bore scope. The scope was pushing water down the bore. It was soaked.

I'm pretty sure that moisture forming in the bore while it is cooling between strings is causing my pressure issue. I've never experienced this before, or even heard of it happening. Has anyone else experienced this? Any ideas on how to prevent it from happening in the future?

I would think the bore would be warm enough to prevent condensation. The barrel would have to be below the dew point???

 

[ELR LVR]

I would think the bore would be warm enough to prevent condensation. The barrel would have to be below the dew point???

Did you ever take a torch to metal to heat it up
And notice moisture forming around the area you are heating?
Even so far as to see droplets of water that you try to push around with the flame?
Many people have thought you are heating the moisture out of the steel
But steel is not porous and does not absorb moisture.
So This is not the case (I was a welder for over 15 years and what we learned during a seminar is)
That is actually condensation............ forming on the steel.......... you are currently heating up
(I forget how exactly it does this, I think from venturi affect of the flame pulling in fresh air around it then condensing it onto the surface)
I never noticed moisture form when I would Tig Weld, as there is not much of a venturi effect there
I never see moisture form on the outside of my woodstove when I spark it up, so we can conclude steel does not absorb moisture
----------------------
Moisture in the air condenses onto the surface. due to the velocity of it rushing in
This is what your condition reminds me of
Is it possible your barrel is pulling in humid air quickly into the barrel, then condensing on the surface just like a torch will condense moisture even onto warm steel?
In nature - Cold Air Rushes to/Fills the Hot Air
-------------maybe keep your bolt closed, or keep your bore purged with Argon

 

[Jager]

Hard to believe moisture is the issue. I'm inclined to believe that the borescope image was illusory. In any case, pushing a dry patch through the bore - if it came out not just dirty with carbon, but also very wet - would be far more definitive.

My guess would be that your load is already hot, but not exhibiting gross pressure signs. The wait between strings is just enough - maybe because ambient temp is slowly increasing; or your box of ammo is sitting in the sun - to push pressures a bit higher, to where you can now see it.

 

[Doom]

Assuming that moisture is actually forming in the bore after shooting it most likely due to condensation of moisture in the residual combustion products. This can occur with a cold barrel. It's not unlike the situation of bringing a cold rifle into a warm room and seeing moisture form on the outside and inside of the barrel.

 

[dantiff2]

I see this inside of my suppressor all the time. It looks completely saturated inside! It happens when I shoot a small string and then pause for a while, to load/work up a few more rounds to shoot.
Dan

 

[PepeLp]

Hard to believe moisture is the issue. I'm inclined to believe that the borescope image was illusory. In any case, pushing a dry patch through the bore - if it came out not just dirty with carbon, but also very wet - would be far more definitive.

My guess would be that your load is already hot, but not exhibiting gross pressure signs. The wait between strings is just enough - maybe because ambient temp is slowly increasing; or your box of ammo is sitting in the sun - to push pressures a bit higher, to where you can now see it.

I ran a bore mop through the bore and it was definitely wet. I was shooting early, trying to beat the wind, it was under 30 degrees outside. I shot 40 rounds the next afternoon with no issues at all and it was in the 60s.

 

[K22]

Following this with interest.

I have shot in all kinds of weather, very cold, very hot, very humid, etc. for over a half century. With few exceptions, all my shots have been cold / cool barrel shots, even at the range because for me, this in my "money shot" being a varmint / predator hunter.

There is no doubt you have some degree of moisture in the barrel since you verified this. The only conclusion I can reach regarding my situation is that I almost never let the barrel become hot to begin with because of my shooting style. I shoot one shot, wait until the barrel cools, then shoot another.

The only time I ever experienced pressure surges was with ball powder in very hot and humid condition in the field.

Also, I have notice condensation on the exterior of firearms take from air-conditioned dwellings to the field or range in highly hot and humid conditions. I have tried to minimize this effect by packing the gear in the truck in the garage the night before or several hours before going outside allow the firearm to slowly acclimate to the weather conditions.

 

[divingin]

Did you ever take a torch to metal to heat it up
And notice moisture forming around the area you are heating?

Little different. Burning hydrocarbons produces CO2 and water. That moisture you're referencing is not coming out of the air, but rather out of the torch.

 

[ELR LVR]

Little different. Burning hydrocarbons produces CO2 and water. That moisture you're referencing is not coming out of the air, but rather out of the torch.

Got it, thanks for the clarification
Main thing was at the time, be corrected in not thinking the moisture was coming out of the steel

 

[Webster]

Did you ever take a torch to metal to heat it up
And notice moisture forming around the area you are heating?
Even so far as to see droplets of water that you try to push around with the flame?
Many people have thought you are heating the moisture out of the steel
But steel is not porous and does not absorb moisture.
So This is not the case (I was a welder for over 15 years and what we learned during a seminar is)
That is actually condensation............ forming on the steel.......... you are currently heating up
(I forget how exactly it does this, I think from venturi affect of the flame pulling in fresh air around it then condensing it onto the surface)
I never noticed moisture form when I would Tig Weld, as there is not much of a venturi effect there
I never see moisture form on the outside of my woodstove when I spark it up, so we can conclude steel does not absorb moisture
----------------------
Moisture in the air condenses onto the surface. due to the velocity of it rushing in
This is what your condition reminds me of
Is it possible your barrel is pulling in humid air quickly into the barrel, then condensing on the surface just like a torch will condense moisture even onto warm steel?
In nature - Cold Air Rushes to/Fills the Hot Air
-------------maybe keep your bolt closed, or keep your bore purged with Argon

Interesting info. I have to come back to there are thousands of rifles his is the only one with water in the barrel?

 

[ELR LVR]

Interesting info. I have to come back to there are thousands of rifles his is the only one with water in the barrel?

The Plot thickens.....very weird man.
This whole thread was actually very enlightening as I had never heard of the phenomenon of moisture building up in a barrel neither. Never even crossed mind. Since if it never happened yet why would a guy think about it right?
This is something good to at least put into the memory log for why pressures may rise.

 

[DShortt]

Little different. Burning hydrocarbons produces CO2 and water. That moisture you're referencing is not coming out of the air, but rather out of the torch.

Very well then. Does smokeless powder contain hydrocarbons?

The condensation issue I had was from taking a rifle out of the 75° air conditioned environment and into 95° or higher air in Midwest summer humidity.

That'll create condensation all over a rifle, including inside the bore. I know this to be fact.

 

[ronemus]

The primary component of smokeless gunpowder is nitrocellulose (carbon, hydrogen, oxygen and nitrogen) and on firing it forms water, carbon dioxide, and oxides of nitrogen. If the barrel is cold (below the dew point of the combustion gases) water will condense. If you're going to shoot a string in cold weather you'll want to start with a warm(ish) barrel to avoid this issue - don't let the barrel cool to ambient temperature.

 

[Webster]

I've got a really weird situation. I'm shooting a 6GT, 105 Berger Hybrid, Alpha Brass bumped .002", 33 gr Varget (weighed), Fed 205 Primer. Running 2,926 with an SD of 6.8.

The other day I shot 5 with no issues, then I took a break for a few minutes. The next 2 shots gave heavy bolt lift and ejector marks, but no increase in velocity. I stopped, pulled the bullets in the remaining rounds and the powder charge was fine. Very strange. Loaded up 10 more with 32.5gr Varget. No issues.

The same thing happened the next day. After a couple with pressure signs, no velocity increase, I stopped shooting and checked the bore with a bore scope. The scope was pushing water down the bore. It was soaked.

I'm pretty sure that moisture forming in the bore while it is cooling between strings is causing my pressure issue. I've never experienced this before, or even heard of it happening. Has anyone else experienced this? Any ideas on how to prevent it from happening in the future?

Your saying the first 5 shots were normal then signs of pressure. Seems impossible that the first shot wouldn't remove moisture. The following 4 shots certainly would. The barrel would be warm after 5 shots. You had a bore scope at the range?

 

[Downhill]

We have shot Service Rifle Matches in light rain, never noticed any issues (other than being uncomfortable). If condensation in a barrel does occur, why do the guys shooting in below freezing temps not report it? Seems like the optimum condition for it to happen.

 

[DShortt]

We have shot Service Rifle Matches in light rain, never noticed any issues (other than being uncomfortable). If condensation in a barrel does occur, why do the guys shooting in below freezing temps not report it? Seems like the optimum condition for it to happen.

Perhaps they do encounter it but fail to recognize it. It's kinda like many things. The taught practices were less than ideal for a long time regarding cleaning practices.
Most here are shooting at less than man-size targets. Close doesn't count. You'll never convince me otherwise because I've observed it personally.
I am not interested in shooting competition matches for many reasons. One of them being that the overall cost is prohibitive.

 

[jelenko]

man-size targets

Well, in Highpower rifle, the targets are hugely generous compared to benchrest groups, but they aren't quite man sized.
X ring is 1 MOA, 10 ring 2 MOA for the prone stages. It's the short range targets [off hand and sitting] that are 1.5 MOA X ring and 3.5 MOA 10 ring - which is just about man sized at 200 yards - but you're shooting either standing or sitting.