RL 26 and bbl throat erosion

[jpretle]

Wondering if anyone has worn out the throat of a bbl using only the RL26 powder and a 105 class bullet. Considering there is a longer burn, therefore a longer 'push' on the bullet, it seems more powder would be burned further down the bbl, resulting in less heat and erosion in the throat area.
Any comments???

 

[rifleman700]

Wondering if anyone has worn out the throat of a bbl using only the RL26 powder and a 105 class bullet. Considering there is a longer burn, therefore a longer 'push' on the bullet, it seems more powder would be burned further down the bbl, resulting in less heat and erosion in the throat area.
Any comments???

Your question is a little vague at best. Cartridge, bbl length and velocity needs to be known before making any determination. And FWIW RL26 is a slow powder but reaches its 95% burn relatively quick compared to other powders in its burn rate area and this along with its heat of explosion is what makes it hard on throats.

Give me a cartridge and bbl length and I will post a graph showing what I mean.

 

[jpretle]

Chambering is 243AI, in a 30" bbl. using 50g of RL26. Velocity is 3400+.

 

[1shot]

If I may, what weight bullet?

 

[jpretle]

If I may, what weight bullet?

105 Berger

 

[1shot]

Have a brand new bbl. chambered in the caliber by accident. My smith says there isn't enough material to cut the chamber in another caliber, so I guess I'll just see how it shoots for mid range.
Thanks,

Lloyd

 

[rifleman700]

105 Berger

Pmax is 55K so this load is way over pressured. 95% burn in 9.5" will be hard on throat.

 

[1shot]

Yep, barrel life won't be it's strong suit!

 

[22BRGUY]

View attachment 994255

Pmax is 55K so this load is way over pressured. 95% burn in 9.5" will be hard on throat.

Gotta say I am impressed!

 

[Kurz]

Pmax is 55K so this load is way over pressured. 95% burn in 9.5" will be hard on throat.

I suggest that you try and run it again but with a couple of appropriate changes.

First, what makes us think that brass for the Ackley version of the .243 Win. cartridge is now valued at 55,000 psi when the same brass in the original form has a pressure standard of 60,191 psi?

Two, we don't know the OAL of his chamber or the freebore or anything else. You 'assumed' it was the Quickload standard of 2.710" the same as the standard version of the cartridge.

Change the pressure rating to the standard 60,191 psi and the OAL to the standard 2.825" and rerun the 'what if'.

Even with Re-25 we are a pinch under 57,000 psi where lower pressure results in less heat. Switch to a cooler burning powder and you reap the benefits of lower pressure AND lower Heat of Explosion but you have a lower velocity.

Personally, I would run VVN-165 or Hodgdon Hybrid 100V and live with the slightly lower velocity.

Regards.

Added: Many of us have talked to and written to Mr. Broemel in attempts to get some of the vagaries straighten out in Quickload. Always it has been to no avail. He refuses to change anything about the program because he is both stubborn and conceited. So, those of us who understand the inadequacies, change them in the program for the benefit of consistency while staying within the realm of safety. You are free to do as you see fit, it's your program.

 

[jfseaman]

It will be a fast lil' bugger.

which means

You might want to be gentle on the repeated shots.

If it's a hunter, it could last the rest of your life.

If it's a range/target/competition rifle. I'd say one to two competition seasons. If you want a number somewhere between 1000 and 2000 rounds but how you treat it could make that 300 to 4000. It's up to you.

 

[Zero333]

H-4831 is great for accuracy and long barrel life in my 243win's.

I don't mind sacrificing a little speed for extended barrel life and superb accuracy.

 

[MagnumManiac]

In regard to powder burn temps, it is my observation using ONLY RE25 for 2 seasons with only ONE setback and re-chambering, that double base powders MUST burn cooler than single base.
In half the rounds using H1000, I had to setback and re-chamber an identical barrel the previous season. It appears that double base powders release more energy and less gas and heat. RE25 does not have a any type of muzzle flash, whereas H1000 is rather large in my 30" barrels.
I am trying Retumbo this season on my short (600yrd) rifle because the groups it produced were the best. I do not expect to get as many shots as RE25.
I only wish RE26 was available here, will be a long wait I think.

Cheers.

 

[rifleman700]

I suggest that you try and run it again but with a couple of appropriate changes.

First, what makes us think that brass for the Ackley version of the .243 Win. cartridge is now valued at 55,000 psi when the same brass in the original form has a pressure standard of 60,191 psi?

Two, we don't know the OAL of his chamber or the freebore or anything else. You 'assumed' it was the Quickload standard of 2.710" the same as the standard version of the cartridge.

Change the pressure rating to the standard 60,191 psi and the OAL to the standard 2.825" and rerun the 'what if'.

Even with Re-25 we are a pinch under 57,000 psi where lower pressure results in less heat. Switch to a cooler burning powder and you reap the benefits of lower pressure AND lower Heat of Explosion but you have a lower velocity.

Personally, I would run VVN-165 or Hodgdon Hybrid 100V and live with the slightly lower velocity.

Regards.

Added: Many of us have talked to and written to Mr. Broemel in attempts to get some of the vagaries straighten out in Quickload. Always it has been to no avail. He refuses to change anything about the program because he is both stubborn and conceited. So, those of us who understand the inadequacies, change them in the program for the benefit of consistency while staying within the realm of safety. You are free to do as you see fit, it's your program.

Not much difference. Case capacity would also change the results slightly.

 

[pete1955]

View attachment 994386

Not much difference. Case capacity would also change the results slightly.

Quickload defaults to the lowest case capacity, as an example the .223 defaults to 28.0 grains of H2O case capacity. But my Lake City cases hold 30.6 which will lower the chamber pressure 6,000 psi.

 

[rifleman700]

In regard to powder burn temps, it is my observation using ONLY RE25 for 2 seasons with only ONE setback and re-chambering, that double base powders MUST burn cooler than single base.
In half the rounds using H1000, I had to setback and re-chamber an identical barrel the previous season. It appears that double base powders release more energy and less gas and heat. RE25 does not have a any type of muzzle flash, whereas H1000 is rather large in my 30" barrels.
I am trying Retumbo this season on my short (600yrd) rifle because the groups it produced were the best. I do not expect to get as many shots as RE25.
I only wish RE26 was available here, will be a long wait I think.

Cheers.

RL25 - 3810 HOE
H1000 - 3630 HOE

Your 95% burn with H1000 had to have been less - quicker than it was with RL25 for it to burn the throat out sooner except that you are seeing a muzzle flash with H1000 which tells just the opposite. Had to be another factor involved.

 

[rifleman700]

Quickload defaults to the lowest case capacity, as an example the .223 defaults to 28.0 grains of H2O case capacity. But my Lake City cases hold 30.6 which will lower the chamber pressure 6,000 psi.

The difference between 28 and 30.6 is 8.5% which is more than what the common Ackley cartridges gain from the parent case - 5-8%

 

[pete1955]

The difference between 28 and 30.6 is 8.5% which is more than what the common Ackley cartridges gain from the parent case - 5-8%

My point was the OP did not give his case capacity and your Quickload chart could be further off again and have a lower chamber pressure with the actual case capacity.

 

[rifleman700]

My point was the OP did not give his case capacity and your Quickload chart could be further off again and have a lower chamber pressure with the actual case capacity.

I understood your point entirely and agree with the case capacity variable. Even changing the case capacity the pressures and velocity change minimally with this size of case. Lower chamber pressure equals lower velocity.

57 grain case capacity - 58,592K 50 grains RL26 3355 fps
60 grain case capacity - 58,572K 51.7 grains RL26 3378 fps

This is a good example of pressure=velocity. With an increase of 1.7 grains the gain was only 23 fps.