Pressure Signs?

[Milton02]

All,

Question for ya'll - I was doing some load development for my 6.5x47 Lapua and started pushing the 140 Berger Hybrids just north of 3000 fps with no heavy bolt lift/primers look fine.

In all the load data I've researched, that seems unrealistic, but my chronograph hasn't lied THAT consistently to me yet. Has anyone experienced these results with the 6.5x47 and am I doing something wrong/bad to my gun?

All knowledge/insight is welcome. Thanks for your time.

-Ian

 

[Barrelnut]

What is the barrel length and miracle powder?

 

[Milton02]

26" barrel
41.5 grains RL-17

I know it seems impossible, but all 5 shots posted just north of 3000 fps.

 

[eklarsen]

According to quickload you are double the max pressure for that load (123,000 psi), so I would say yes, you are doing something bad to that gun and **** lucky it didnt destroy it..

 

[Mikecr]

Stop

 

[Bowfishn]

My QL shows 41.5gr RL17 with 140 Berger Hyb to be 2933 fps @ 66,688 psi (over max load), but to get 3000+ with 140 Berger Hyb with RL17 out of a 6.5x47 Lapua 26" barrel it takes just over 73,000 psi 10,000 over max, not a recommended load.
2.800 " coal 48.00 gr h2o case capacity.

 

[Bowfishn]

You are not showing pressure signs because they do not always show up until way over pressure.

I showed no pressure signs at 3040+ fps with 49.0 gr RL26 with143 ELD-X bullets out of my 6.5 Creed. 26"barrel 2.890" coal 52.70 gr H2O case capacity. Vel checked with Magnetospeed.

QL showed 2981 fps @ 61,193 psi with 49 gr RL26, But pressures had to be 68,877 psi for 3047 fps with RL26, had to adjust burn rate for my powder lot.

I can get just at 3000 fps with 143 ELD-X bullets and that is teetering on the edge of max.

 

[CatShooter]

26" barrel
41.5 grains RL-17

I know it seems impossible, but all 5 shots posted just north of 3000 fps.

That load will put you somewhere around 52Kpsia - which is light... the velocity you are getting is about 100 fps fast, which is within variances.

It is nothing to worry about.

 

[RockyMtnMT]

Are you running a skyscreen chronograph in the bright sunlight? I have had this show very high vel. It still runs consistent just high. Could explain some of the situation.

Steve

 

[Pdvdh]

Are you running a skyscreen chronograph in the bright sunlight? I have had this show very high vel. It still runs consistent just high. Could explain some of the situation.

Steve

What brand chrono? Or chronos if more than one?

 

[Pdvdh]

Has anyone experienced these results with the 6.5x47 and am I doing something wrong/bad to my gun?

All knowledge/insight is welcome. Thanks for your time.

-Ian

Reload the same, single casing multiple times to see if the primer pocket expands. If it doesn't expand and primers continue to seat with resistance after 5 shots fired, you couldn't be generating dangerously high pressure in your rifle.

The case head will expand in the first several firings if you're over pressuring. In a single firing if you're way over pressure.

The brass case head, primer pocket, and primers are the weakest links in the entire system. As pressures rise, the case head will expand and grow in diameter, resulting in loose and/or leaky primer pockets.

Having said all that, if you're significantly over maximum MVs compared to the reloading manuals, you need to monitor pressure signs with extra efforts.

 

[eklarsen]

terribley sorry, I see my cartridge information didnt update correctly giving bogus results. I see the load now shows 66,712 pressure not double that as I said before.

 

[CatShooter]

terribley sorry, I see my cartridge information didnt update correctly giving bogus results. I see the load now shows 66,712 pressure not double that as I said before.

No ice cream for you !!

 

[Mikecr]

So Milton02, was this new brass, or fire formed brass that you were load developing with?