Custom build: which cartridge for maximum accuracy if only shooting factory ammunition

[SDHNTR]

This is like asking a doctor which are the best donuts to eat.

 

[Truck24hr]

All those guys that said 6.5CM, i'm with them for right now.

So much great factory hunting ammo available, and shootability, leaves no better choice right now.

That may change in a few years though.

 

[jjcausey22]

6.5 Creedmoor or 6.5 PRC, depending on barrel length and max kill range.

Rifle will be between 7.5 and 8 pounds without an optic or suppressor. I really want a 20-22 inch barrel and I’ll shoot it suppressed at all times. Would like the capability to shoot game at 500-600. That could possibly increase if I get better at reading and calling wind. I will probably shoot eld-m’s in factory ammunition because I want the most margin of error with wind out to those distances.

 

[elkguide]

For accuracy with factory ammo, I would look at .300 Win Mag - .308 - 6.5 PRC as my first 3.

 

[nm.otter]

Rifle will be between 7.5 and 8 pounds without and optic or suppressor. I really want a 20-22 inch barrel and I’ll shoot it suppressed at all times.

Adding an optic and suppressor to that should make 6.5 CM a viable choice.

My suppressed 20" 6.5 CM (7 pounds 15 ounces all in) is on the hairy edge of workable spotting shots from 140-147gr slugs. 120s are noticeably easier, so I'm giving serious thought to 6mm GT.

 

[hereinaz]

Rifle will be between 7.5 and 8 pounds without an optic or suppressor. I really want a 20-22 inch barrel and I’ll shoot it suppressed at all times. Would like the capability to shoot game at 500-600. That could possibly increase if I get better at reading and calling wind. I will probably shoot eld-m’s in factory ammunition because I want the most margin of error with wind out to those distances.

IMO, 20” 6.5 PRC for 600.
22” 6.5 creed can get you there, but less margin of error for wind.

Just know you will need to focus more to manage recoil. But, either are doable suppressed.

 

[hereinaz]

Adding an optic and suppressor to that should make 6.5 CM a viable choice.

My suppressed 20" 6.5 CM (7 pounds 15 ounces all in) is on the hairy edge of workable spotting shots from 140-147gr slugs. 120s are noticeably easier, so I'm giving serious thought to 6mm GT.

Such a nice cartridge the 6 GT.

 

[bojangles808]

6.5cm. my 20in is a 600 yd gun at mountain DAs with eldms

 

[Sled]

Of your listed cartridges, I'm with the 6.5cm crowd. If you need more, you find hot factory ammo or step up to the PRC. I've had great luck with my CM shooting berger classic hunters and rarely pull out the PRC anymore. Since eagle eye ammo has had QC issues, I'll be looking into Form's recommendation of federal loads.

This might be only my opinion but I believe the Hornady chamberings are well thought out and inherently lead to less errors from tolerance stacking. In my limited experience I've had more precise rifles, factory or custom, from those Hornady chamberings. Maybe somebody with more knowledge or experience can say why or refute that.

I'll add that even though I like the creedmoor, I am not a millennial, do not wear a flat brim hat, nor do I have a man bun.

Good luck with your decision.

 

[jjcausey22]

@nm.otter has a chart with bore to capacity ratio of many popular chambering. It’s been interesting to see how some cartridges that are commonly cited to be “accurate” or “shootable” will group closely with each other on that chart.

If only shooting factory ammo, I would second what @Formidilosus listed above. 6mm Creedmoor as my number 1 pick. And stock up on federal gold medal match ammo.

Where is that chart

 

[TaperPin]

I’ll be the odd man out and go with a 7 mag and no turn neck (.315”). Its minimal dimension neck still allows factory loads, but has to be kept clean. Typically these also have minimal dimensions in the throat. 7 Rem mag has a wide variety of quality bullet choices and while certain factory loads in other cartridges are often used in competition, not much is left on the table with the 7 mag or many other common cartridges. The same could be said for a good quality 300 wm.

Not every custom barrel is the same - get the best one you can from an accuracy minded gunsmith and I’d put that against 99.9% of the custom guns out there.

 

[nm.otter]

Where is that chart

N

Post in thread 'Spotting your shot, most import factors.'

Friday at 8:56 PM

Good powders are good in the case dimensions they excel at. H4350 in a Creedmoor case at creedmoor pressures is a good example. Very repeatable and reliable. But try and fit it into a larger or smaller case, and funny things can happen.

Case capacity to bore area ratio rears its head once again. Here's a table of some common cartridges sorted by this Ratio -- dividing the usable case capacity (to bottom of neck) by the square of the bore diameter. It's a dimensionless number which can be derived either from inches or from mm/ml:

Charge efficiency, barrel life...

• nm.otter

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[jimh406]

I'd lean Hornady calibers since they were designed for target shooting with tight chambers. Note: I don't own a Hornady caliber.

 

[SouthernCharm]

Ask the builder which ammo do they spec their guns too. They will tell you which factory ammo will shoot mom or better. Then ask them if a certain cartridge is more accurate.