25 Pronghorn Preliminary Range Report

[cal30_sniper]

I finally got out to the range with preliminary load dev for my Tikka 25 Pronghorn build (25-300 WSM). I'll try to keep this thread updated as work progresses, but initial results are very promising.

The rifle:

• Tikka T3X stainless action (6.5PRC rebarrel)
• Preferred Barrel Blanks Tikka Light Hybrid, 20" fluted barrel
• High Desert bottom metal
• Waters Rifleman short magnum magazine
• Rokstok (thanks @hereinaz!)
• TBAC muzzle device and Ultra 7 suppressor (will eventually get an OG 6.5 OTB can)
• UM Medium 30mm Rings
• Maven RS1.2

The load:

• ADG 270 WSM brass necked down with Redding 25-300WSM dies
• Hornady 134gr ELDM
• Federal 215M primers
• N570 powder
• 3.070" COAL

I worked up from 67.1grs of powder to 69.6grs of powder (95-98% case fill) using Gordon's Reloading Tool to find a starting point. 3 shots at each step of 0.5grs. ~5mins between shots to avoid barrel torching.

Velocities exceeded the predicted values from GRT by about 130fps. I stopped at 69.6 grs, which averaged 3100fps with 11.1SD over 3 shots. Starting load gave 2984fps with a 9.1SD. All 3 shot groups were 1MOA or less (average 3-shot group size was 0.73MOA). Groups are attached so as not to smoke the screen on your mobile devices.



Ejector marks that could be seen, but not felt with a fingernail, showed up at 69.6grs. Next steps will be to back down around 68.8grs (~3050fps) and shoot some 10rd groups there to verify groups and ensure no pressure signs show up. Barrel only has 20rds down it, so I do anticipate it to speed up somewhat over the next few groups.

Overall I'm super pleased. Recoil is non-existent, accuracy potential looks great, and it's slinging those nice long high BC bullet at better than anticipated velocities. N570 is also surprisingly easy to load with (I haven't used it before this).

P.S., I know 3rd groups are statistically meaningless. Hold your horses for some 10rd groups to follow.

 

[jjohnsonElknewbie]

I finally got out to the range with preliminary load dev for my Tikka 25 Pronghorn build (25-300 WSM). I'll try to keep this thread updated as work progresses, but initial results are very promising.

The rifle:

• Tikka T3X stainless action (6.5PRC rebarrel)
• Preferred Barrel Blanks Tikka Light Hybrid, 20" fluted barrel
• High Desert bottom metal
• Waters Rifleman short magnum magazine
• Rokstok (thanks @hereinaz!)
• TBAC muzzle device and Ultra 7 suppressor (will eventually get an OG 6.5 OTB can)
• UM Medium 30mm Rings
• Maven RS1.2

View attachment 958973

The load:

• ADG 270 WSM brass necked down with Redding 25-300WSM dies
• Hornady 134gr ELDM
• Federal 215M primers
• N570 powder
• 3.070" COAL

View attachment 958977

I worked up from 67.1grs of powder to 69.6grs of powder (95-98% case fill) using Gordon's Reloading Tool to find a starting point. 3 shots at each step of 0.5grs. ~5mins between shots to avoid barrel torching.

Velocities exceeded the predicted values from GRT by about 130fps. I stopped at 69.6 grs, which averaged 3100fps with 11.1SD over 3 shots. Starting load gave 2984fps with a 9.1SD. All 3 shot groups were 1MOA or less (average 3-shot group size was 0.73MOA). Groups are attached so as not to smoke the screen on your mobile devices.

View attachment 958990

Ejector marks that could be seen, but not felt with a fingernail, showed up at 69.6grs. Next steps will be to back down around 68.8grs (~3050fps) and shoot some 10rd groups there to verify groups and ensure no pressure signs show up. Barrel only has 20rds down it, so I do anticipate it to speed up somewhat over the next few groups.

Overall I'm super pleased. Recoil is non-existent, accuracy potential looks great, and it's slinging those nice long high BC bullet at better than anticipated velocities. N570 is also surprisingly easy to load with (I haven't used it before this).

P.S., I know 3rd groups are statistically meaningless. Hold your horses for some 10rd groups to follow.

First off, very cool that somebody is posting on here about this cartridge. I was torn between it and the 6.5 WSM, and ended up going with the 6.5. I'm using the 147 ELDM and chose N565 based on a scouring of the internet for load data. I've never used this powder before, and the rods meter excellent out of my Horndady auto dispenser. I plan to get out and shoot mine today for groups and will post later. Mine has factory Tikka 24", and I may try N570 if MV isn't where I want it. On the same note, in your 20" barrel, you may see a bump in MV with 565 or 560 if the 570 doesn't get it where you want. Anyways, good luck and keep us in the loop on your results.

 

[SlimCreaper25]

This is bad to the bone! Keep us updated, I’ll be curious where this goes.

Did you have to neck turn? I did for a 6 WSM but I started with 300 WSM brass.

Where did you find a reamer??


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[cal30_sniper]

This is bad to the bone! Keep us updated, I’ll be curious where this goes.

Did you have to neck turn? I did for a 6 WSM but I started with 300 WSM brass.

Where did you find a reamer??


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No neck turning required. Preferred Barrel Blanks has the reamer, which is listed as a 25-300WSM. I didn’t see a print, but he may have one on file for it. I figure it’s likely that the reamer itself accommodates for the greater neck thickness. Necking down from 270 WSM brass it’s hardly noticeable.

 

[SlimCreaper25]

Nice! I’ve got a 20” 25 cal carbon 6 coming and was going to do a 25-7PRC. How come you went with the Pronghorn??


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[cal30_sniper]

Nice! I’ve got a 20” 25 cal carbon 6 coming and was going to do a 25-7PRC. How come you went with the Souper??


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I was originally going to do a 25-7PRC. I changed my mind when looking at COAL and realizing the WSM had just as much powder capacity but would fit in a Rem 700 short action.

Then I decided to build on a Tikka instead of a 700, so that didn’t really matter anymore, but I was already stocked up on ADG 270 WSM brass.

 

[SlimCreaper25]

I get that! I’ve got a Defiance XM that’s currently a 300 WSM. Plan to rebarrel to a 25-7PRC but it will barely fit.. May have to try the Pronghorn


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[cal30_sniper]

I get that! I’ve got a Defiance XM that’s currently a 300 WSM. Plan to rebarrel to a 25-7PRC but it will barely fit.. May have to try the Pronghorn


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That’s exactly what I was looking at. Squeezing the 25-7 into a Defiance Ti-X Medium vs room to spare with the Pronghorn.

Then I ended up putting the Pronghorn into the Tikka and building a long throat 300 WSM with the Ti-X medium, haha. Great minds think alike.

 

[cal30_sniper]

How do you like 6WSM? I’ve had a hard time understanding why so much effort has been put into 6SAUM improved (6UM) when 6WSM could be done easier with what seems like the same result.

 

[SlimCreaper25]

That’s what I ended up doing. 20” Long throat 300 WSM. 215 hybrids at 3.210” and H4350 at like 2740 fps. Great combo!! Love the WSM case


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[SlimCreaper25]

How do you like 6WSM? I’ve had a hard time understanding why so much effort has been put into 6SAUM improved (6UM) when 6WSM could be done easier with what seems like the same result.

Big fan of it so far. It’s 16” and shoots 108 at 3070. It hammers. Hoping to wax a blacktail with it soon.

Here’s a little write up I did. Need to update it soon but so far so good

https://rokslide.com/forums/threads/6-wsm-load-development.411004/

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[cal30_sniper]

Big fan of it so far. It’s 16” and shoots 108 at 3070. It hammers. Hoping to wax a blacktail with it soon.

Here’s a little write up I did. Need to update it soon but so far so good

https://rokslide.com/forums/threads/6-wsm-load-development.411004/

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Very nice. I’ve also been messing with 6-284, which I’ve really enjoyed so far. I’m waiting to get my hands on some of the new Norma 105gr Bondstrike bullets to try in it.

 

[jjohnsonElknewbie]

Very nice. I’ve also been messing with 6-284, which I’ve really enjoyed so far. I’m waiting to get my hands on some of the new Norma 105gr Bondstrike bullets to try in it.

LOL, great minds... I have a 25-284 and was thinking about a 6-284 as well. However, a guy can essentially reproduce with a 110 ELDX or 115 VLD, although you lose a little BC. Decided it wasn't worth a new build for marginal gains, if any.

What mag did you go with for your Tikka 25 WSM? I went with HCA gen 2 mag and bolt stop.

 

[cal30_sniper]

LOL, great minds... I have a 25-284 and was thinking about a 6-284 as well. However, a guy can essentially reproduce with a 110 ELDX or 115 VLD, although you lose a little BC. Decided it wasn't worth a new build for marginal gains, if any.

What mag did you go with for your Tikka 25 WSM? I went with HCA gen 2 mag and bolt stop.

I used the Waters Rifleman 0018 mag. This particular load takes up the whole thing.

I also picked up a 0022m mag, which will allow loading to 3.38” if I run into a longer bullet I want to shoot.

I kicked around the 6-284 vs 25-284 for a long time, but am real happy with the 6 so far. 25-284 is a very well balanced cartridge with the heavy .25 bullets. One build living in my head is a 257 Bob AI to shoot the 110/115 class bullets. That’d give my 6.5x55s a run for their money with a little less recoil. I also like the idea of the 6mm Rem, but its shoulder is so far back it would make more sense to do a .243 AI or neck down the .257 AI.