Blown primer in .243 Ackley

[thwatson2]

Looking at some sites like Hodgdon, Speer and nosler. Looks like 44 grains is max for 4831sc. I know others are pumping more but temp, bullet seat depth, and primer type can have effects like you are describing. Hope you figure it out. Think i'd Step back to start load of 38 grains and start chronographing as I stepped up. Had problem couple years ago with varget in 308. Loaded some mediocre loads and I was chronographing 30-06 velocities. Primers were showing signs of pressure issues, etc. stepped the load way back and seemed to do well. Remember all the loads developed online, in books and someone else's load can be a different story in your gun. Good luck

 

[Bulletspitter]

So to obey our new lead free law I'm starting to load up ammo for my hunting rifles.

First up is my .243 Ack, my go to rifle that has always shot 105gr Berger's

I cleaned it real good with Shooters Choice like I always do. It's a Broughton 5c so it cleans up extremely easy.

I loaded 5 of the 95gr Barnes LRX with H4831SC.

I started at 46 then 47, 48, 49, 50 based on loads I found online and QL calcs.

First shot at 46gr the bolt barely opened and the primer was in the mag box!!!! Plugging the 46gr load into QL comes up with 45,248 psi...I know there's lots of variables with QL and I accounted for the ones I know. Even still, this load is low compared to everything I've found.

I went back and pulled the remaining bullets and weighed the powder charge, all were correct. It was also a new unopened jug of powder.

Any ideas????

Did you get your chamber good and dry after cleaning? If you had any cleaning agent in the chamber, it could add pressure, and blow primers.

 

[glbhunter]

Barnes bullets have shown higher pressure than a lead jacked bullet every time I have used them and you might have a tighter bore. It would be good to look at Barnes data book. I loaded some Barnes bullets one time in my 25-06 using low end of powder charges. It also blew out a primer. I pulled them all and started lower next time they did ok after that but didn't have the accuracy I expected so I used different bullets. However, a few years later in my 220 swift I developed a load using reloaded 15 and Barnes 52 gr tsx flat base (was hoping for a bullet that holds together and it does) and will shoot a 1/4 inch group if I can do it. I have shot that load past 4000 and I settled for 3850 which is the most accurate. All guns and reloading components are different and each must be loaded to its own likening which I am sure you are aware. Good luck.

 

[JMyrkle]

So to obey our new lead free law I'm starting to load up ammo for my hunting rifles.

First up is my .243 Ack, my go to rifle that has always shot 105gr Berger's

I cleaned it real good with Shooters Choice like I always do. It's a Broughton 5c so it cleans up extremely easy.

I loaded 5 of the 95gr Barnes LRX with H4831SC.

I started at 46 then 47, 48, 49, 50 based on loads I found online and QL calcs.

First shot at 46gr the bolt barely opened and the primer was in the mag box!!!! Plugging the 46gr load into QL comes up with 45,248 psi...I know there's lots of variables with QL and I accounted for the ones I know. Even still, this load is low compared to everything I've found.

I went back and pulled the remaining bullets and weighed the powder charge, all were correct. It was also a new unopened jug of powder.

Any ideas????

My question to you is are you using a hand priming tool or are you using a press to seat your primers? Inhave had problems with Lapua brass before having loose primer pockets and blowing primers out this is why I use a hand priming tool so I can feel how the primers set into the primer pocket. Also Barnes bullets being made from solid copper create higher pressures when the bullet enters the lands and can cause pressure spikes. This can be remedied by hand lapping the throat area. One way to check and see if this is the problem is to check your barrel for heavy copper deposits(hard to remove), if these are present you need to lap the throat as there may be small burs that are atomizing small amounts of copper from your bullets. That condition will also cause a pressure spike as the bullet seats in tin the rifling. Just things to check and good luck

 

[TX Badger]

Do you have access to another can of H4831sc?

While loading for my 25-06 a few years ago I had a partial can of H4831sc that I started development with. I was running 115 bergers a little over 3200. Opened a new can to do some fine tuning and went to the range, shot my first 3 shot string and grabbed my target during cease fire. The range officer looked at my target and said the 200yd target looked pretty good with a .7" group. Then I showed him the primers, one was flat and 2 popped, and I was at 3400. Went home backed down the load to well lower than what I was using with the previous can, still popped primers. Threw that can away.

Unfortunately, I switched to H1000 after that and never tried another can of H4831sc for comparison. Hogdon was shocked of course when I called and sent me a replacement can.

 

[reubenski]

I've run 45gr of 4831SC in two 243 barrels. 46gr SHOULD not be too hot in an AI. That said Ive seen as much as 120fps variation between jugs of 4831SC. Regardless 46gr obviously isn't going to work for you. Frankly, it does sound like a carbon ring. I would look around for a bore scope so you can see it and understand what it looks like. I recommend CLR. Carbon rings can be extremely stbborn and the amount of brushing required with a more mild solvent makes me pause. Not sure I'd eawa to subject my barrel to that. Use an aggressive solvent and keep a soaked patch in the throat with a jag for 20 mins or more at a time. Brush with a bronze brush. Patch out and use the borescope to monitor progress. Good luck

 

[coyotezapper]

So to obey our new lead free law I'm starting to load up ammo for my hunting rifles.

First up is my .243 Ack, my go to rifle that has always shot 105gr Berger's

I cleaned it real good with Shooters Choice like I always do. It's a Broughton 5c so it cleans up extremely easy.

I loaded 5 of the 95gr Barnes LRX with H4831SC.

I started at 46 then 47, 48, 49, 50 based on loads I found online and QL calcs.

First shot at 46gr the bolt barely opened and the primer was in the mag box!!!! Plugging the 46gr load into QL comes up with 45,248 psi...I know there's lots of variables with QL and I accounted for the ones I know. Even still, this load is low compared to everything I've found.

I went back and pulled the remaining bullets and weighed the powder charge, all were correct. It was also a new unopened jug of powder.

Any ideas????

I was going to read the whole thread before making a comment but there is too many things here that are wrong to start with.

1. You mention QL data so lets start there. First off the new 6mm LRX 95 bullet has not been updated in QL. There should be an update this month. Assuming that another X" bullet of the same weight is the same is WRONG. I don't know where you got your QL data above but it does not mirror my data. 46 grains is almost max and 50 grains is 68K with standard "TSX" bullet. PMAX for the 243AI is 55K.

2. Barnes bullets - solids do not obturate like lead core bullets so they have to be jumped so the initial pressure does not spike. There is a reason Barnes recommends jumping them .050" to begin with and then adjust moving away from the lands if needed for tuning.

3. Did you adjust your case capacity in data point in QL? Different case capacities will change pressures.

I am not going to comment any further because to me its obvious what you should do. You need to start over with the bullet seated .050" off of the lands and start your testing over. Start at 42 grains moving up and look for a velocity of 3100 fps. Don't get caught up trying to determine pressure by looking at your case. By the time pressure swipes or other indicators show up you are past pmax.

The Barnes bullets are excellent bullets and easy to load. Do not be afraid to jump them over .100" if needed as they will shoot excellent at these lengths. Pat attention to remaining velocity when determining the bullets effective range. This bullets limit is 1800 fps. Once it drops below this velocity its performance suffers.

Also, you mentioned Hammer Bullets not having the B.C.'s you are looking for. You need to look at them again. Hammer Bullets have a higher B.C. than Barnes. They list theirs as a G7 and Barnes G1.

 

[BC54]

Obturate - my new word for the day. Thanks.
Obturate works for me. Also, don't solid bullets deform, butter, compress, or have different friction characteristics passing through the barrel than lead based bullets? I assume that solid bullets would be harder than jacketed lead bullets and thus have higher pressures than jacketed lead bullets of the same mass/weight. Since solid bullets are not as dense as jacketed lead bullets wouldn't that also result in less useable case volume? And being less dense, the bearing surface would be longer as well?

 

[reubenski]

I was going to read the whole thread before making a comment but there is too many things here that are wrong to start with.

1. You mention QL data so lets start there. First off the new 6mm LRX 95 bullet has not been updated in QL. There should be an update this month. Assuming that another X" bullet of the same weight is the same is WRONG. I don't know where you got your QL data above but it does not mirror my data. 46 grains is almost max and 50 grains is 68K with standard "TSX" bullet. PMAX for the 243AI is 55K.

2. Barnes bullets - solids do not obturate like lead core bullets so they have to be jumped so the initial pressure does not spike. There is a reason Barnes recommends jumping them .050" to begin with and then adjust moving away from the lands if needed for tuning.

3. Did you adjust your case capacity in data point in QL? Different case capacities will change pressures.

I am not going to comment any further because to me its obvious what you should do. You need to start over with the bullet seated .050" off of the lands and start your testing over. Start at 42 grains moving up and look for a velocity of 3100 fps. Don't get caught up trying to determine pressure by looking at your case. By the time pressure swipes or other indicators show up you are past pmax.

The Barnes bullets are excellent bullets and easy to load. Do not be afraid to jump them over .100" if needed as they will shoot excellent at these lengths. Pat attention to remaining velocity when determining the bullets effective range. This bullets limit is 1800 fps. Once it drops below this velocity its performance suffers.

Also, you mentioned Hammer Bullets not having the B.C.'s you are looking for. You need to look at them again. Hammer Bullets have a higher B.C. than Barnes. They list theirs as a G7 and Barnes G1.

What chamber pressure do you think one is at when primers are blowing out the back of a case?

 

[Buttermilk]

You might be surprised at how close to the lands you are with that Barnes compared to a Berger.

I'd certainly measure them and see exactly where you are. The Barnes bullet construction is completely different than a Berger (stating the obvious here). I also believe Barnes recommends being at least 0.050" off the lands with their bullets.

 

[adam32]

Also, you mentioned Hammer Bullets not having the B.C.'s you are looking for. You need to look at them again. Hammer Bullets have a higher B.C. than Barnes. They list theirs as a G7 and Barnes G1.

Hammer doesn't make one for an 8 twist that compares with the LRX for BC.

 

[coyotezapper]

Obturate - my new word for the day. Thanks.
Obturate works for me. Also, don't solid bullets deform, butter, compress, or have different friction characteristics passing through the barrel than lead based bullets? I assume that solid bullets would be harder than jacketed lead bullets and thus have higher pressures than jacketed lead bullets of the same mass/weight. Since solid bullets are not as dense as jacketed lead bullets wouldn't that also result in less useable case volume? And being less dense, the bearing surface would be longer as well?

Other than the initial start pressure I have seen no difference between solids and cup and core bullets. Its a hard comparison because of the bearing surface difference between each can create different pressure curves on this difference alone. Some of the most accurate bullets I have shot were lathe turned solids.

 

[coyotezapper]

Hammer doesn't make one for an 8 twist that compares with the LRX for BC.

The 88 is close. You can make up the difference in higher velocity. Don't get caught up in B.C. as there are other factors that matter more - terminal performance.

 

[coyotezapper]

What chamber pressure do you think one is at when primers are blowing out the back of a case?

Hard to say. I have only had it happen to me once and that was with a 223rem and H335 powder through a bolt gun and I did not have my 43 hooked up so I didn't know the pressure.