6.5CM - Hornady CX 130 grn blowing primers - Help

[Lee2495]

I'm a bit perplexed.

I am trying work up a load in my 6.5cm (24" 1:8 twist) for the Hornady 130grn copper CX.

I full resized some once fired Hornady brass (53.48 H2O grains of capacity), trimmed to length and loaded with...

41.9grn of Vit N160.

This should have been my starting load, but when fired it it blew the primer out of the pocket and left an impression of the extractor pin in the bottom of the case. I clearly stopped and didn't go any further.

I'm confused as there is not data for N160 for the CX but all the listed 130 grn loads are roughly between 40 - 44 grn so I thought starting in the middle and working up in 0.5grn increments would be safe.

This load also showed in QL as 98.7% fill so I was not worried about a compressed load. Also showed as 2536 fps so I thought it would not be an issue (used the closes bullet available).

Was thinking of starting at 39 grn and working up or is this still to hot. Also need to be effective at range while stalking.

Alternatively I have some N140 but not sure this would have enough poke for the 130rgn CX in 6.5cm.

Thoughts and advice would be appreciated.

Thanks,
Lee

 

[User00040]

I'm a bit perplexed.

I am trying work up a load in my 6.5cm (24" 1:8 twist) for the Hornady 130grn copper CX.

I full resized some once fired Hornady brass (53.48 H2O grains of capacity), trimmed to length and loaded with...

41.9grn of Vit N160.

This should have been my starting load, but when fired it it blew the primer out of the pocket and left an impression of the extractor pin in the bottom of the case. I clearly stopped and didn't go any further.

I'm confused as there is not data for N160 for the CX but all the listed 130 grn loads are roughly between 40 - 44 grn so I thought starting in the middle and working up in 0.5grn increments would be safe.

This load also showed in QL as 98.7% fill so I was not worried about a compressed load. Also showed as 2536 fps so I thought it would not be an issue (used the closes bullet available).

Was thinking of starting at 39 grn and working up or is this still to hot. Also need to be effective at range while stalking.

Alternatively I have some N140 but not sure this would have enough poke for the 130rgn CX in 6.5cm.

Thoughts and advice would be appreciated.

Thanks,
Lee

I'd go and look for some Superformance powder.



Don't load them long, seat the bullet so the case neck is on the end of the drive band.

 

[takbok]

Firstly, don't start in the middle of the charge weights - start at the lowest charge.

You can't substitute jacketed bullet data for most copper bullets - start with the Vihtavuori Barnes data for The 127gr LRX (38.6gr). Load the bullets to the Hornady specified OAL for a start.

 

[Border]

And compressed loads are not anything to worry about.....

 

[takbok]

I would forget Quickload etc too when there's load data available for similar bullets. A basic chronograph is a great help.

Verify for yourself whether it's a compressed load or not rather than relying on a theoretical program.

I'm not trying to preach but it sounds like you need some pointers.

 

[User00033]

I'm a bit perplexed.

Google will un-perplex you in about 3 seconds.

Not hard to find this stuff fellas….

 

[Lee2495]

Thanks for the tips.

Unfortunately I don't have a chronograph...yet...i have worked up loads for my .243 many times successfully without it.. perhaps the Creedmoor ,might be the catalyst for a purchase!

I will use the load data for the 127gr LRX. and work up from there.

I seated the bullets to the Hornady stated COL of 2.810" which is just touching the base of the lower band. this seemed like a good starting point.

 

[Lee2495]

Google will un-perplex you in about 3 seconds.

Not hard to find this stuff fellas….

View attachment 285297

Had this data and looked at the burn rate chart to try and get an equivalent charge for N160 to reconfirm the vit load data assumption. Clearly asumption is the mother of all F£$K ups!

 

[User00033]

I will use the load data for the 127gr LRX. and work up from there.

What?

Why?

 

[Eric the Red]

N140 would appear to be a better fit as a powder than N160.

Theoretical pressures for N160 are way down on the specs you've listed, so there's something else going on IMO.

At the risk of teaching Grandma, check the bullet (and powder) are not mislabelled - check your scales and charge weights - and you've made no mention of seating depth or neck tension. Something is inflating your pressure - a lot.
My recommendation is to find something awry before reloading another batch.

 

[User00033]

Our posts are crossing.

N160 is slightly slower (only a little bit) than H4350. You started towards the top end of the load data but I am very surprised that it blew out the primer.

I think there’s something else wrong.

For the sake of your eyesight and a bunch of other stuff please start all over again with first principles. Have you got a COAL gauge and have you used it to check the position of your lands?

 

[Lee2495]

Good advice, I am going to pull the lot and start from scratch. I only fired one of the rounds and checked the case for pressure signs.

I will triple check everything as I go.

I checked the length with decent venner callipers, set the die high then screwed it in until reached 2.810". I was going to start with this COAL and then adjust after I found a sweet spot with the load.

 

[nowler]

Have you adjusted the start pressure for a copper bullet in QL?

 

[Foxyboy43]

Hmm. I may be mistaken but a quick look at Viht’s site suggests you were only 0.1gns off their heaviest max for any 130gns bullet listed!

 

[Lee2495]

Have you adjusted the start pressure for a copper bullet in QL?

How do you do that??

 

[Lee2495]

Hmm. I may be mistaken but a quick look at Viht’s site suggests you were only 0.1gns off their heaviest max for any 130gns bullet listed!

No, it goes up to 44grn for a 130grn round. I was using 41.9.

 

[Foxyboy43]

No, it goes up to 44grn for a 130grn round. I was using 41.9.

Correct - long day out plus age plus old eyes. Apologies L.
Nurse!!

 

[Heym SR20]

Start low and work up. I always do a ladder test - start at base load working up in 0.2 gn increments, with one load at each.

With copper bullets load to COAL - and they like a bit of space before hitting the lands.

Primers backing out can also be a sign of lower pressure. They are pushed back by the initial gas pressure and then the case expands back to the bolt face. If charge is too low case may not expand enough.

Real signs of pressure are sticky bolt handles and really flattened primers that mushed into the case head.

 

[Bowland blades]

My guess is .... You oversized the brass ! N160 would not be my choice n150 or even N140 perhaps ?
if the shoulders dont need pushing back on bolt feel , dont do FLS ! Oh and just double check your primer type is absolutely correct

 

[Muir]

My guess is .... You oversized the brass ! N160 would not be my choice n150 or even N140 perhaps ?
if the shoulders dont need pushing back on bolt feel , dont do FLS ! Oh and just double check your primer type is absolutely correct

Do you mean that FL sizing and setting the shoulder back increased the pressures? That won't sit well for the guys shooting Ackley chamberings. ~Muir