Pressure issues, need some help

[dellet]

I will measure when I get back into the reloading room. The throat is past gone in this rifle. I know the 107 smk is seated maybe 2/3 into the neck and doesn’t touch the lands

And that raises another potential problem. If the throat is gone, extremely long jump, what can happen is a huge pressure spike. The bullet starts moving and the pressure behind it builds higher do to the time elapsed to the long jump, then hitting the lands acts like an obstruction and it spikes.

Back to what I said earlier, jump, jam, charge weight changing chamber volume is a balancing act. A bullet that leaves the neck before it hits the lands is a wild card. 296/H110 earned a nasty reputation for blowing up revolvers for this very reason.

Adding that you will want to know where touch is, not just that it is not touching. You need to know how much erosion there is.

 

[Doom]

And that raises another potential problem. If the throat is gone, extremely long jump, what can happen is a huge pressure spike. The bullet starts moving and the pressure behind it builds higher do to the time elapsed to the long jump, then hitting the lands acts like an obstruction and it spikes.

Back to what I said earlier, jump, jam, charge weight changing chamber volume is a balancing act. A bullet that leaves the neck before it hits the lands is a wild card. 296/H110 earned a nasty reputation for blowing up revolvers for this very reason.

Adding that you will want to know where touch is, not just that it is not touching. You need to know how much erosion there is.

Not sure what he means by the throat being gone but for the scenario you mention it would probably be extreme. I don't have personal experience with this but do know it has been hypothesized and it makes sense.

 

[DLT]

And that raises another potential problem. If the throat is gone, extremely long jump, what can happen is a huge pressure spike. The bullet starts moving and the pressure behind it builds higher do to the time elapsed to the long jump, then hitting the lands acts like an obstruction and it spikes.

Back to what I said earlier, jump, jam, charge weight changing chamber volume is a balancing act. A bullet that leaves the neck before it hits the lands is a wild card. 296/H110 earned a nasty reputation for blowing up revolvers for this very reason.

Adding that you will want to know where touch is, not just that it is not touching. You need to know how much erosion there is.

I can get that information. Just not around the bench right now, the bullet is not out of the case before it hits the lands

 

[barefooter56]

Yes I did but that doesn’t explain much to me as to what happened. I was using vv load data not a max charge. unless it’s a big no no to use large rifle primers in place of small rifle data. I just switched powders like any of us has done hundreds of times. I did not have my scale set wrong or use an out of line powder.

I have made mistakes before but with a little work or asking the right questions I found out and learned why things did what they did. Not sure about this go round.

Small rifle primer and large rifle primer load data are the same. Also VV load data is very conservative so there may be some other issues here.

 

[DLT]

Small rifle primer and large rifle primer load data are the same. Also VV load data is very conservative so there may be some other issues here.

Lot no.

 

[Doom]

Seeing as how the Gun Shop you mentioned (if its the one I suspect) is reputable that clears that up. And the powder is current so it shouldn't be an issue.

I will mention one thing about VV but it's not related to N160. In 2023 or 2024 they dropped the charge for max in 308 with a 168 SMK from 42.1 at 2697 fps to the current 40.1 AT 2569 FPS. However I shoot a Rem 700 308 with a lot of freebore so I almost have never seen pressure and any published max. Phil wasn't able to give me any specific reason. Of note the 223 data for the 52 SMK did not change. I had no issues at 42.1 but my powder is from 2015,

 

[DLT]

Seeing as how the Gun Shop you mentioned (if its the one I suspect) is reputable that clears that up. And the powder is current so it shouldn't be an issue.

I will mention one thing about VV but it's not related to N160. In 2023 or 2024 they dropped the charge for max in 308 with a 168 SMK from 42.1 at 2697 fps to the current 40.1 AT 2569 FPS. However I shoot a Rem 700 308 with a lot of freebore so I almost have never seen pressure and any published max. Phil wasn't able to give me any specific reason. Of note the 223 data for the 52 SMK did not change. I had no issues at 42.1 but my powder is from 2015,

I’m going with powder problem. No issues using h4350 or R16 with any primer or adg brass or sig brass. I have been reloading eh maybe 20 years I have goofed up but so far never accidentally dialed my scale wrong or put the wrong powder in the wrong container. I HAVE, however threw powder and forgot to size the necks and threw powder without priming. Still do it, luckily I throw the first row in tray then seat bullets to get them out of the way so my mistakes get caught early lol

 

[Doom]

put the wrong powder in the wrong container.

Yep. fortunately it was a small amount of Varget and 8 lbs of IMR 4064.

threw powder without priming

Yep, but only a few.

My worst was get some bolt gun neck sized brass confused with some AR FLS. Rounds stuck in a AR can be a b___h!

 

[DLT]

Yep. fortunately it was a small amount of Varget and 8 lbs of IMR 4064.

Yep, but only a few.

My worst was get some bolt gun neck sized brass confused with some AR FLS. Rounds stuck in a AR can be a b___h!

Haha yes it can. My shooting buddy just tried some n160 he bought for a 260rem. Took it up to 44gr with a 140eldm. I told him 44gr of my powder would blow his gun up

 

[DShortt]

Haha yes it can. My shooting buddy just tried some n160 he bought for a 260rem. Took it up to 44gr with a 140eldm. I told him 44gr of my powder would blow his gun up

Well as stated many times already, that powder needs to be used for lawn fertilizer.

 

[DLT]

Well as stated many times already, that powder needs to be used for lawn fertilizer.

Thought about chrono his loads. Then start super low with mine and see just how much faster my jug is. Could be a possible test

 

[DShortt]

Thought about chrono his loads. Then start super low with mine and see just how much faster my jug is. Could be a possible test

And you might eat a bolt. For a jug of powder?

I'm out.

 

[DLT]

And you might eat a bolt. For a jug of powder?

I'm out.

I’m not. He said he wanted to. I told him better not. I’ll get it poured out before he gets it

 

[dellet]

You should shoot some of what he has.

 

[DLT]

You should shoot some of what he has.

Now there is a better idea