Alliant AR Comp for .308 Win

[Dr. Strangelove]

Morning all,

Has anyone used Alliant AR Comp in .308W? On paper it seems viable but there doesn’t seem to be a huge amount of firsthand experience out there, at least this side of the pond.

Their loads for it are here - Alliant Powder - Reloader's Guide

In case you’re wondering, those are max loads and they say to reduce by 10% to find the starting load!

Also, any reason to go for AR Comp over Reloder 15/Ramshot Tac/CFE 223?

Cheers,

Dr. S

 

[borbal]

P-Max internal ballistics would suggest AR Comp is a bit quick for bullets heavier than about 130 grains

 

[Dr. Strangelove]

P-Max internal ballistics would suggest AR Comp is a bit quick for bullets heavier than about 130 grains

Thanks, it would appear that to drive a 150gr bullet at 2,800fps then RL15 would be a happier choice!

 

[Dr. Strangelove]

As an alternative, Alliant Power Pro 2000MR could do well. @borbal how hard would it be to add that in to P-Max?

 

[NigelM]

AR Comp is one of three Alliant powders that are very temperature insensitive along with RL16 and RL23. I have tested RL16 in a number of different chamberings (not 308Win) and have found their claims to be true, with zero difference between -5 deg C and +30 deg C. I'm also getting very low ES and accurate groups. I have not tested AR Comp but as part of the same family of powders I have no reason to think that it would not behave the same way. I've not had a need to use it as it's a bit quick for my applications.

AR Comp "heat of explosion" is much lower than RL15, as is RL16. RL15 has nuked a couple of barrels for me and it looks like RL16 is quite a bit easier on them because of that lower heat of explosion.

So there are two reasons to give it a try. Looks quite good in QL.

 

[Dr. Strangelove]

AR Comp is one of three Alliant powders that are very temperature insensitive along with RL16 and RL23. I have tested RL16 in a number of different chamberings (not 308Win) and have found their claims to be true, with zero difference between -5 deg C and +30 deg C. I'm also getting very low ES and accurate groups. I have not tested AR Comp but as part of the same family of powders I have no reason to think that it would not behave the same way. I've not had a need to use it as it's a bit quick for my applications.

AR Comp "heat of explosion" is much lower than RL15, as is RL16. RL15 has nuked a couple of barrels for me and it looks like RL16 is quite a bit easier on them because of that lower heat of explosion.

So there are two reasons to give it a try. Looks quite good in QL.

Cheers Nigel, much appreciated!

 

[borbal]

As an alternative, Alliant Power Pro 2000MR could do well. @borbal how hard would it be to add that in to P-Max?

I will have a look

 

[Dr. Strangelove]

I will have a look

Thank you!

 

[cjs66]

Thanks, it would appear that to drive a 150gr bullet at 2,800fps then RL15 would be a happier choice!

For those numbers, what’s wrong with N140? If you can get it.

cjs

 

[Dr. Strangelove]

For those numbers, what’s wrong with N140? If you can get it.

cjs

I’m keen to use a 175gr bullet. Was playing with 150gr boat tails the other day and only getting 2700fps with 45gr of N140. According to P-Max, to get up to 2,800 the pressure would be getting up a bit. Although the data output seemed a bit fast (although within 100fps as stated) compared to the real world results.

 

[borbal]

As an alternative, Alliant Power Pro 2000MR could do well. @borbal how hard would it be to add that in to P-Max?

Alliant 2000-MR has now been added to P-Max internal ballistics

What length barrel are you using? How are you measuring your usable case capacities?

 

[Dr. Strangelove]

Alliant 2000-MR has now been added to P-Max internal ballistics

What length barrel are you using? How are you measuring your usable case capacities?

To be fair, I was using a value for a Lapua case that I scrounged off the internet. I have a set of syringes arriving tomorrow so will use your method with one of my once-fired Lapua cases with the bullet seated at the shallowest depth I used the other week!

 

[Dr. Strangelove]

Alliant 2000-MR has now been added to P-Max internal ballistics

What length barrel are you using? How are you measuring your usable case capacities?

Having just measured case capacity properly, I got 51gr water. Plugging that into PMax gave 2,744fps which, although a touch high, is much closer to my average velocity!

 

[borbal]

Well done!

 

[Dr. Strangelove]

Well done!

Thanks. If anyone needs a hobby syringe let me know - I’ve got five more than I’ll ever need!

 

[borbal]

What length is your barrel?

 

[Dr. Strangelove]

What length is your barrel?

24.25” measured from the muzzle to the bolt face.

 

[Littlekilmory]

It’s worth double-checking the case volume: new Lapua brass generally hold 55.3 (+/-) grains and most other makes run between 54 and 56. These figures measured over some years and agree with ‘Quickload’.
N140 is great with sub 155grain bullets but I prefer N150 for the heavier ones. Both are kind to barrels, too.

 

[Dr. Strangelove]

It’s worth double-checking the case volume: new Lapua brass generally hold 55.3 (+/-) grains and most other makes run between 54 and 56. These figures measured over some years and agree with ‘Quickload’.
N140 is great with sub 155grain bullets but I prefer N150 for the heavier ones. Both are kind to barrels, too.

This was measured with once fired Lapua brass with my projectile of choice seated. So that gave me the usable case capacity which is what PMax calls for.

 

[Littlekilmory]

My once-fired Lapua cases read 55.5 using a primer pocket blank and a tiny touch of washing up liquid to ensure full fill. I use a digital scale calibrated beforehand. Case volume and seating depth make big changes in pressure so I’m perhaps a bit obsessive...