Yet another quarterbore project on the way

[stagpanther]

I tried them with my 6.5 CM's and 22 CM in the past, and couldn't come close to getting the same velocities that I get with proven loads with other brass.

My target velocity is 2,850 fps with the biggest 25 cal bullets. In the Aipha brass I'm not very far from that in the low-end load I shot--but to be honest I haven't done any real development yet--this load was just a function test. Are you necking your brass up/down from some other caliber? I have most makes of 6.5 and 6 creedmoor brass, might consider trying that. I'm not a routine 1000+ yd shooter so getting max velocities (and burning out a barrel under 1000 rounds) is not a priority for me.

 

[Txhillbilly]

My target velocity is 2,850 fps with the biggest 25 cal bullets. In the Aipha brass I'm not very far from that in the low-end load I shot--but to be honest I haven't done any real development yet--this load was just a function test. Are you necking your brass up/down from some other caliber? I have most makes of 6.5 and 6 creedmoor brass, might consider trying that. I'm not a routine 1000+ yd shooter so getting max velocities (and burning out a barrel under 1000 rounds) is not a priority for me.

Yes, I neck down 6mm CM brass for my 22 CM, and 6.5 CM brass for my 25 CM. The barrel life on the 25 CM should be in the 2500 - 3000 round range, I think you'd have a hard time doing it in 1000 rounds.
I got over a 1000 rounds out of my first 22 CM barrel, and I hot rod the hell out of it.

 

[stagpanther]

This weekend was the first time this year I've had the "all clear" to go as long as I wanted, so I popped my 5HD on my new 25 creedmoor build and took it out to 359 yards. Wasted more shots than I thought I would finding the range--but did find a nice group of the 135 bergers driven by 41.2 grs of H4350. I was getting around 2,850 fps which is pretty much the target velocity range I was aiming for, so I'll come back to this load for further exploration. Full disclosure--I did spaz and pull one (5th) shot badly--it didn't even hit the target.

 

[stagpanther]

The Shilen barrel is amazing and can shoot way beyond my abilities, I ordered another one as an eventual replacement--or maybe another build. I've reached the conclusion that IMO the 25 creedmoor is probably the best all-around choice for the modern .257 highSD/BC bullets at present, when I factor in velocity, powder consumption and barrel wear/endurance. It doesn't happen all the time with all the groups; but I have repeatedly seen dual bullet impacts that were almost perfectly concentric.

As a side note, I was curious to see how well the barrel would do with some of the very high BC bullets like PVA's 120 gr Seneca; a solid lathed bullet which is very long for the weight and who's bearing surface is pretty far back from the center of the bullet--which means it has a long jump before engaging the leade. Still shoots them very well.

 

[stagpanther]

110 gr Badlands bulldozer

I had tried these in my 25 PRC and decided to try them in my 25 creedmoor as well. They are "waisted" bullets and not as big as the 135 gr bergers which the freebore on the barrel was specifically cut for--meaning it, like the PVA Seneca, has a long jump to engage the leads but it doesn't seem to be much of deterrent to accuracy. The Bulldozer is a hunting bullet and doesn't have as high a BC as other bigger .257 bullets; "only" G1 .570 and G7 .292--but my gut feeling tells me that they may possibly be underrating that (!). The Redding seating stem seems to crush down the nose insert when seating. I found what appears to be a good node at 40.9 grs using VV N555. I think the powder is a bit slow since I was seeing notable muzzle discharge, though no flash as far as I can tell. I might try a magnum primer to see if that makes any difference. Once again I managed to blow the group by not keeping the rifle steady through one of the shots--but the 4 shots inspire me to keep trying.

 

[stagpanther]

Today's menu consists of PVA 120 gr Seneca very high BC solids. Using VV N160 this time, a bit faster and a bit finer cut than N555. These bullets are literally needle-nose sharp and can poke a hole in your hand if you're not careful. I gotta get a new seating stem worked out for the Redding die--for all the money they charge for a custom die--and the fact the 25 creedmoor was specifically created with the newer high SD/BC bullets in mind--I don't get why it has a lower ogive nose angle.

 

[stagpanther]

Shot the PVA senecas and they were "OK"--producing groups in the .8 MOA range but I've become greedy knowing the rifle can shoot well under that. Time to contact Redding--the seating stem and die plug screw is all one piece so there is no option for replacing a ogive/nose profile insert. I'd kinda like to know what the die actually is profiled for--it deforms all the high BC bullets I've tried so far.

 

[stagpanther]

I've been dragging my feet on doing one last step in optimizing this build--because I've been having so much fun shooting it --and that is modding it to take advantage of MDT's AICS pattern 308/6.5 creedmoor magazine which comes without a front binder plate. This gives you the potential to load your cartridges all the way out to a COL of just a microbe's hair shy of 2.97"--a hefty gain over the standard magazine and even the AICS magazine with binder plate.

Problem is, almost all standard production short action receivers magazine inlets and feed ramps are cut short closer to the standard 2.8" so you'll need to machine out a little extra room giving the cartridge the necessary clearance. In addition, the feed lips on the magazine will need to be slightly modified to put a slight pitch up to the cartridge to ensure the bullet nose does not smack into the barrel's tennon face. Luckily, I've done this quite a few times with my AR creedmoor builds, and in fact this mod on a bolt gun receiver was much easier in comparison to doing the same on an AR receiver.--and also results in a much longer potential COL.

 

[stagpanther]

After putting the rifle back together I decided to continue trying different buttstocks--the CTR is a great one but I have a bit of trouble at times keeping the rifle from sliding back and up, so I replaced the CTR with a BCM SOPMOD--very nice and tight buttstock and has a level shelf instead of one that slants back like the CTR. Loaded up 10 x 110 gr bulldozers and tested the new setup at 177 yds; after shooting a couple of foulers I shot this 8 shot group which while is quite nice I still pulled some of the shots as they broke. I'm certain a better shooter than me (and I consider myself only a little better than average) could make one small hole at 200 yds out of 10 shots.

 

[stagpanther]

I read so often about the different aspects of a rifle's barrel and ammunition as being sources of dispersion--I know in my case the single biggest factor in shot consistency--is me. A good rifle will tell you that, a bad one will tell you no matter what you do things are not going to improve.

 

[stagpanther]

I'm toying with the idea of taking this rifle to a bench rest match because I've had some stellar groups with it; but I would be going up against 30BRs and don't want to be embarrassed too badly. So I kinda tried to see how low I could go with bullet weights and still get good groups; on my rifle that's about 110 gr with a bullet like the badlands bulldozer. Since it's a boat tail and has a higher BC than the flatbase 30BRs I was kinda hoping maybe that might even the playing field for me at long distance in winds. Unfortunately did not work out as I had hoped.

Winds were pretty light around 10 to 12 mph, but switchy from every direction with mid-day thermals tossed in for good measure. It was hopeless for me to try to pick a prevailing direction/velocity over the entire 355 yards so I instead picked when it looked like the stronger prevailing winds were most sustained over the greatest distance. Out of the 10 shots I took that worked for 6 of them, but not the other 4. Mirage on the bare gravel and dirt was a bit of a nuisance too, The only way I've found to mitigate that somewhat is to dial down the magnification as far as I can.

 

[stagpanther]

Speaking of classic .257 cartridges--just received notice my .257 Weatherby barrel is finally on its way. Already got the rest of the parts lined up rare'n to go.

 

[ligonierbill]

Who is supplying your barrel?

 

[stagpanther]

Normally I would go with Shilen or Criterion through Northland--but decided to try X-Caliber on one of their sales. Can't vouch for X-Caliber like I can for Northland as it is my first from them, I've heard both (mostly) good and some bad--but that's the nature of firearms business in general.

 

[USAF Ret]

Well, y'all got me on the quarter bore bandwagon. I just ordered a 25-45 Sharps barrel. My dad has been hunting with that cartridge for the last several years and took his biggest buck to date at about 250 yards. I have heard, "You ought to go with this or that instead." However, this is a nostalgia cartridge as his hunting days are about over and figured I would pick that up. Ought to be fun.

 

[stagpanther]

Well, y'all got me on the quarter bore bandwagon. I just ordered a 25-45 Sharps barrel. My dad has been hunting with that cartridge for the last several years and took his biggest buck to date at about 250 yards. I have heard, "You ought to go with this or that instead." However, this is a nostalgia cartridge as his hunting days are about over and figured I would pick that up. Ought to be fun.

It's kinda a "one trick pony"--but is indeed tremendous fun--and often overlooked as a potential soft-shooter for medium sized game. I have an AR in it and found this load which shot a 1-holer using Ramshot exterminator and 90 gr GKs.

 

[USAF Ret]

It's kinda a "one trick pony"--but is indeed tremendous fun--and often overlooked as a potential soft-shooter for medium sized game. I have an AR in it and found this load which shot a 1-holer using Ramshot exterminator and 90 gr GKs.

I appreciate the information, sir. What kind of velocity are you getting from that load?

 

[stagpanther]

I appreciate the information, sir. What kind of velocity are you getting from that load?

This is out of an AR--you probably would do better with a bolt gun I would think--but I recorded 2,650 fps and 1404 ftlbs energy at the muzzle. As always, your results may vary--start low--and you use the information at your own risk.

 

[stagpanther]

135 gr berger long range hybrid; currently the biggest commercially-produced .257 bullet that I'm aware of. Despite its extreme length--it almost falls out of the case mouth before the base of the ogive engages the lands. Now I'm glad I didn't add any more freebore length. Seating the bullet shank the distance of the caliber left me with a COL of around 3.55."