Help me pick my next cartridge - 25cal

[284winner]

My experience with RL17 is both happy and not. I very like its energy to pressure ratio as I could get 3000+ velocity without pressure problems, however RL17 is very temperature sensitive. This past July, shooting at Spearpoint, I saw my velocities increase 50 to 60 fps over the course of five hours from a relatively cool 8 am to a quite hot 1 pm. This necessitated numerous adjustments to my ballistic app to remain on target (1400 yds) and of course many missed shots. I didn't do enough temperature testing this year, lesson learned.

Ya heard that before. Luckily I hunt with all my rifles and always set drop data for 30° temps. No difference if temps drop 20° or rise 10°. Kinda in my temp range annually.

 

[SweaterDood]

Well, what did you pick?

Nothing, yet. Still leaning toward the 25 GT. One of my main concerns was that I didn’t have much inventory of SRPs, since I only use them for .223 Rem, currently. Well I recently came into a few thousand, which will last the life of the barrel. My thought is that, to scale, the GT case for the .257 should rival the Dasher for the 6mm. I feel that the cartridges should be very similar in behavior.

 

[SweaterDood]

Try 25 in a 6.5 PRC

I don’t want a magnum boltface, and the case won’t be optimized in a short action. Basically just a lot of wasted powder, extra recoil, and poor barrel life

I've suspected RL17 would fuel my 25-284 as good or better than any other powders. It's the fastest for my 284 running 160-180s hands down. I'm gonna give it a try once I get some load data with RL26 with the 131s. Hoping it'll be a good substitute

RL17 and Hodgdon Superformance are supposed to behave quite similarly in the .257-6.5mm bores. As far as speed Norma MRP has given the best performance with terrific accuracy. Temp stability is fair. Definitely work up loads on the hot end of the climate for safety. RL23 & RL26 should basically improve on the stability for the same speed.

I have been using N165 recently in my 257 QPC, which is just slightly lower in capacity than the 284 case. I am getting a nice node around 3115 fps using it. I did not see any pressure signs from my initial test, but it was only the 2nd firing on the brass, the 1st being virgin case to the improved chamber. I don’t resize the case body until after the 2nd firing, so charge weight will change slightly but I have a very fine range to explore.

With MRP, H100v (bad stability, almost dangerous), PP4000MR I have seen a node around 3120 as well. I think the blackjack bullet likes this speed for atmospheric entry (personal theory on velocity turbulence nodes...). I’ve been playing with odd powders since the better options have been extremely limited...

 

[284winner]

I don’t want a magnum boltface, and the case won’t be optimized in a short action. Basically just a lot of wasted powder, extra recoil, and poor barrel life



RL17 and Hodgdon Superformance are supposed to behave quite similarly in the .257-6.5mm bores. As far as speed Norma MRP has given the best performance with terrific accuracy. Temp stability is fair. Definitely work up loads on the hot end of the climate for safety. RL23 & RL26 should basically improve on the stability for the same speed.

I have been using N165 recently in my 257 QPC, which is just slightly lower in capacity than the 284 case. I am getting a nice node around 3115 fps using it. I did not see any pressure signs from my initial test, but it was only the 2nd firing on the brass, the 1st being virgin case to the improved chamber. I don’t resize the case body until after the 2nd firing, so charge weight will change slightly but I have a very fine range to explore.

With MRP, H100v (bad stability, almost dangerous), PP4000MR I have seen a node around 3120 as well. I think the blackjack bullet likes this speed for atmospheric entry (personal theory on velocity turbulence nodes...). I’ve been playing with odd powders since the better options have been extremely limited...

N165 is interesting.

 

[std7mag]

Well, with the GT, there is Alpha brass.
Should be a simple neck up or down.

My 257 Roberts really likes Hybrid 100V.
Tried MRP in the 257 Roberts AI. It didn't seem to like it. Seemed too slow burning. Did much better with RL19.

 

[SweaterDood]

Well, with the GT, there is Alpha brass.
Should be a simple neck up or down.

My 257 Roberts really likes Hybrid 100V.
Tried MRP in the 257 Roberts AI. It didn't seem to like it. Seemed too slow burning. Did much better with RL19.

A slicked up nitride mandrel works great for necking up to .256” in a single pass. I’ll probably get a bushing die too, mainly for playing with the spring back rate and making minor tension adjustments. Photo attached is a piece of 6GT Alpha brass necked up to 25GT with a blackjack stuffed in. I’m still considering the 47L case too, because Lapua makes brass. Although both the Hornady and newer Alpha brass seem to be holding up well with the added strength of the SRP Case head... And Hornady brass is only $0.75/pc vs $1.15 for the 47L

I shot a PRS match with H100v that went from frost on the ground to hiding under trees for shade by noon. 100fps velocity swing over the course of the day and some pressure issues developed. Never seen another powder that bad. Testing was impressive though. Colder climates should be safer. My MRP load was hot, but safe, but I have the luxury of a 3.225” COAL in my action, throated accordingly for the 130 class bullets.

N165 is interesting.

I’m having great success with it. Temp and humidity stability has been great for me so far

 

[284winner]

A slicked up nitride mandrel works great for necking up to .256” in a single pass. I’ll probably get a bushing die too, mainly for playing with the spring back rate and making minor tension adjustments. Photo attached is a piece of 6GT Alpha brass necked up to 25GT with a blackjack stuffed in. I’m still considering the 47L case too, because Lapua makes brass. Although both the Hornady and newer Alpha brass seem to be holding up well with the added strength of the SRP Case head... And Hornady brass is only $0.75/pc vs $1.15 for the 47L

I shot a PRS match with H100v that went from frost on the ground to hiding under trees for shade by noon. 100fps velocity swing over the course of the day and some pressure issues developed. Never seen another powder that bad. Testing was impressive though. Colder climates should be safer. My MRP load was hot, but safe, but I have the luxury of a 3.225” COAL in my action, throated accordingly for the 130 class bullets.



I’m having great success with it. Temp and humidity stability has been great for me so far

Any idea how it does against RL26 performance wise ? I'll be running some loads with RL26 soon. May look for some N165 next.

 

[Beiruty]

Try 25 CrdM, I run sims for a person who is interested in this wildcat

 

[SweaterDood]

I'd say, after 3 6GT barrels, that the 25GT would be out. Unless you want to go through the aggravation
of making it from x47 Lapua brass.
That being said, pick one that can be made from Lapua brass ( x47 or Creed). One of the guys I shoot PRS
with is running a 25-08AI. Don't know any details on the reamer, but in 15 mph wind, he doesn't have to hold off of a full size IPSC at 1000 yds.

Not sure how I missed this post earlier... Please explain what you don’t like about the GT. If it’s the brass we’re you using the Hornady, gen1 Alpha, or gen2 Alpha? I’ve heard that the early Alpha brass had issues, but a lot of people swear by the Hornady and updated Alpha lots.

I have recently been looking into the power factor requirements for NRL Hunter and I am doubtful that the 25GT would have enough muscle to make it. 2820fps seems like a big ask. Blackjacks testing indicates that the 25x47L can get into the mid 2900s so i should be able to comfortably meet the PF requirements, by going this route. The hunter matches wouldn’t be my main focus, but I do want to try them, and don’t want to fool with too many chamberings right now.

 

[SweaterDood]

Try 25 CrdM, I run sims for a person who is interested in this wildcat

I refuse to run a crudmop. No need for sims. Plenty of real world data readily available from Blackjack bullets initial testing. Same for 25x47L

@284winner N165 is a single base, so not as much energy as RL23/26, but similar burn rate. Supposedly burns very cool which interested me. I haven’t hit pressure yet with it, but last time I went out I didn’t beat the storm and didn’t finish my load testing. Couldn’t see the berm, much less the target at 100yds...

 

[284winner]

I refuse to run a crudmop. No need for sims. Plenty of real world data readily available from Blackjack bullets initial testing. Same for 25x47L

@284winner N165 is a single base, so not as much energy as RL23/26, but similar burn rate. Supposedly burns very cool which interested me. I haven’t hit pressure yet with it, but last time I went out I didn’t beat the storm and didn’t finish my load testing. Couldn’t see the berm, much less the target at 100yds...

Kinda wondering about N570. Heard some guys using it in 25-06 with the 131s

 

[Fuj]

Kinda wondering about N570. Heard some guys using it in 25-06 with the 131s

N-555 But like everything else, good luck finding it

 

[kindabitey]

Not sure how I missed this post earlier... Please explain what you don’t like about the GT. If it’s the brass we’re you using the Hornady, gen1 Alpha, or gen2 Alpha? I’ve heard that the early Alpha brass had issues, but a lot of people swear by the Hornady and updated Alpha lots.

I have recently been looking into the power factor requirements for NRL Hunter and I am doubtful that the 25GT would have enough muscle to make it. 2820fps seems like a big ask. Blackjacks testing indicates that the 25x47L can get into the mid 2900s so i should be able to comfortably meet the PF requirements, by going this route. The hunter matches wouldn’t be my main focus, but I do want to try them, and don’t want to fool with too many chamberings right now.

The main issue I had was a weird neck tension problem with Alpha OCD brass. New and 1x fired was fine, but on the second sizing, It wouldn't hold a bullet. It would measure good with a gauge pin at .002 neck tension,
but could push the bullet down on top of the powder by hand. I sent two or three emails to Alpha via their website, but never got a response.
The first gen. Alpha was OK, but the Hornady worked the best.
Other than the brass issue, it was mediocre at best. I went through 2 Stuteville/ Bartlien and 1 Hawk Hill/ Hawk Hill and never got close much more than Dasher speeds from it. When I closed out my last one, it was at 2850 w/ Hornady 105 bthp, which is only 40 fps faster than my last 6BR.

 

[SweaterDood]

The main issue I had was a weird neck tension problem with Alpha OCD brass. New and 1x fired was fine, but on the second sizing, It wouldn't hold a bullet. It would measure good with a gauge pin at .002 neck tension,
but could push the bullet down on top of the powder by hand. I sent two or three emails to Alpha via their website, but never got a response.
The first gen. Alpha was OK, but the Hornady worked the best.
Other than the brass issue, it was mediocre at best. I went through 2 Stuteville/ Bartlien and 1 Hawk Hill/ Hawk Hill and never got close much more than Dasher speeds from it. When I closed out my last one, it was at 2850 w/ Hornady 105 bthp, which is only 40 fps faster than my last 6BR.

Strange. Did you have any other odd indicators like heavy fouling on the outside of the necks? Maybe the neck portion of the chamber was too large and weakening the necks? Both builders you listed are well respected so I assume they use a good reamer.

Also were you using a bushing, mandrel, or honed die to set tension?

I have a couple local guys that shoot the 6GT in my club and they seem to get around 3000fps from 28” barrels. Not sure of manufacturer, but they have both rebarreled to the 6GT again and have been happy. I love hearing all sides and opinions though.

 

[kindabitey]

All three of mine were 26". I do tend to run all of my stuff on the lower end, however, I got caught in a bit of rain at a match earlier this year, and with a very conservative load (35.0 gr. SW Long Rifle and 109 LRHT) had heavy bolt lift with OCD brass. Luckily, I only had to shoot one stage after the rain started, and it was inside of the conex.
While all of this is probably minor, and could have been resolved, I didn't feel like it was worth the effort over switching back to a 6BR.

 

[SweaterDood]

All three of mine were 26". I do tend to run all of my stuff on the lower end, however, I got caught in a bit of rain at a match earlier this year, and with a very conservative load (35.0 gr. SW Long Rifle and 109 LRHT) had heavy bolt lift with OCD brass. Luckily, I only had to shoot one stage after the rain started, and it was inside of the conex.
While all of this is probably minor, and could have been resolved, I didn't feel like it was worth the effort over switching back to a 6BR.

I had a storm come though last time I went out for load development. I was hoping to finish before it passed through, but didn’t quite make it. I was getting to the top of my powder range for the day and decided to call it off. Rain/extreme humidity can do some funky things to an otherwise normal load, so I thought better of continuing that particular day.

Since looking into the power factor requirements of the NRL Hunter game, I don’t see enough margin in the GT case to keep velocity above the 2820 FPS needed with the 135 LRHBT. Looks like a 25x47L will be the ticket. It also gives me some comfort that I’ll be able to use Lapua brass as well. Lots of data already surrounding this combo. Next steps will be to make some calls and start planning the build.

 

[358WCF]

A little late to the party, but count another vote for the Souper. For no other reason than I've been eyeballing one of these since the 1st time I read thru Ackley's book.

If'n it was me, & since I'd likely be buying at least 1/2 the reamer, & trimming cases is right up there with a trip to the dentist, I would go with an improved case. Not necessarily a 40* Ackley, but maybe an RCBS Improved. I think they were 28* or 30* with a touch more body taper than an Ackley. Dies will cost the same as any other custom. Plentiful 308 (7-08, 260, 243) brass, you can name it whatever you want, & nobody else will have one.

 

[284winner]

A little late to the party, but count another vote for the Souper. For no other reason than I've been eyeballing one of these since the 1st time I read thru Ackley's book.

If'n it was me, & since I'd likely be buying at least 1/2 the reamer, & trimming cases is right up there with a trip to the dentist, I would go with an improved case. Not necessarily a 40* Ackley, but maybe an RCBS Improved. I think they were 28* or 30* with a touch more body taper than an Ackley. Dies will cost the same as any other custom. Plentiful 308 (7-08, 260, 243) brass, you can name it whatever you want, & nobody else will have one.

Buddy of mine put together a 25 Panther improved (30° improved based off .260 case). Technically a 25 Souper but Jim Carmichaels original name of his 260 when he wildcatted it. Offers him about 90 fps less performance than the 25- 284. Cool round and very sexy looking to boot. Feeds well too from mags.

 

[SweaterDood]

Buddy of mine put together a 25 Panther improved (30° improved based off .260 case). Technically a 25 Souper but Jim Carmichaels original name of his 260 when he wildcatted it. Offers him about 90 fps less performance than the 25- 284. Cool round and very sexy looking to boot. Feeds well too from mags.

For this application, there is no point to be above 2900fps. There will be a good node there. The 131 & 135 are too long to seat optimally in an AICS mag in the .308 case. The SAW pushes the neck junction back toward the shoulder junction, making a more efficient form of improvement on this case, and is achieved by a single pass through the sizing die. If I want to go the route with the highest safety factor for speed, the SAW fits the bill. At the same time, ES/SD typically are least when the case is near 100% fill with a powder yielding nearly 100% burn in the barrel. Smaller more efficient cases get the edge here.

I don’t have need for a rifle that can only hunt paper or steel though, so I do want a viable cartridge. I particularly like the NRL Hunter’s minimum Power Factor requirement for this purpose. No video-game, recoil-less, baby cartridges. The 25 cal bullets are about as small/light as possible while still being competitive. The 131 blackjack requires MV ~2900fps to make PF. The 4 extra grains of the 135 Berger brings the requirement down to 2820fps. So the 25x47L at 2860-2880 should be safely above minimum and at a nice place for recoil in a 14-16lb rifle.

 

[SweaterDood]

So an email from Blackjack regarding JGS reamers in stock came the other day...

Long story short:
A 1:7.5t Brux HV and a 25x47L No Turn / .130” FB reamer are headed my way!