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View Full Version : Rechambering for a target tactical caliber... That isn't 6.5 caliber.



isacpotatoes
07-11-2019, 07:03 PM
Any recommendations on what I should rechamber my 10 FCP-SR in? (I guess the SR isn't entirely relevant since the factory barrel is threaded, but not necessarily the new barrel.) Sidenote: I live in California, so moderators or Flash hiders are fine on a bolt gun, not suppressors obviously.

I've learned rifle marksmanship on a .308 and .223. I'm interested in investing in a new barrel chambered in something other than my current Savage (.308).

I don't have an interest in shooting a 6.5, not because I don't believe the hype; rather I just refuse to be a bandwagoner. A friend has a RPR that shoots well I'm 6.5. I guess I rather pursue something else.

I've done some research on 7mm-08, but most of it seems to pertain to hunting. I'm open to getting a hunting rifle chambered in 7mm-08, but for now my .270 should do. 7mm caliber seems pretty interesting, and I feel like it could be a winner in a short action.

The advantage to .308 though seems to be that it doesn't require or rather doesn't benefit as much from barrel length in regards to velocity. So a 20" does well for target shooting or hunting. Reloading obviously changing the dynamics of the rifle.
In short, I've been told bigger bore rifles exhaust gas faster and therefore burn it faster/sooner. Overbore I think is the term?

So with say a 7mm-08, I imagine it would benefit more from a 22-24" barrel, /reloading/handloading even more so.

Does anyone have experience shooting 7mm calibers for target shooting in a short action?

If so, would I be better suited to a 7wsm or SAUM? Or another caliber? An advantage to 7mm seems to be the bigger weight offerings that 6.5/.260 doesn't seem to have beyond 140's and 143's.

I'd like to hear suggestions.

Thanks,

Isacpotatoes


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RCE1
07-11-2019, 07:40 PM
I have the Savage GRS which came chambered for 6.5CM. I just had to try it, but, as luck would have it, there was an issue with the factory barrel, so I ordered a Criterion. Since I have a ton of 6mm bullets in stock, it made more sense for me to switch to 6mm Creedmoor, so I did. That way, all I lose is the need for 6.5mm projectiles and I can still use the 6.5mm Lapua brass necked down to 6mm. When my mentor (who has since passed away) learned I was getting into the 6.5CM, he asked my why, when there has been SO much research and development for 6mm bullet designs in the benchrest community, especially the long range guys who shoot at 600 and 1000 years. I managed to get the new setup to the range and its really sweet. I think I found an adequate load on my first trip, although I'm sure there's room for improvement. The 6.5CM barrel never shot any better than 1.5" at 100, which was a great disappointment. I understand my situation was probably not the norm, but the Criterion barrel I got as a 26" varmint weight prefit is so much nicer than the original.

Another rifle I've been experimenting with is the 7mm or .284 Shehane. It's kind of a modified .284 Winchester, but it got there the hard way. It's credited with getting long action performance in a short action rifle, although with heavy bullets you may have magazine problems. My version is on a Barnard single shot action and drives tacks at 500m.

wbm
07-11-2019, 08:21 PM
If you are going for target shooting go with 6mm.

Blackthorn
07-11-2019, 10:02 PM
I agree with wbm. 6mm BR or a 6mm Dasher. 284 would be a good choice as well. Love Dashers super accurate but they eat barrels.

grouse
07-11-2019, 10:38 PM
Hard to beat the prices of factory 6.5 ammo.

bsekf
07-12-2019, 07:55 AM
6x47L

Coyote_Hunter
07-12-2019, 08:59 AM
It isn't just hype with the Creedmoor cartridges (6mm and 6.5mm). The Saami chamber and cartridge specs are held to tighter tolerances than typical cartridges, especially in the critical throat area, which is specified at a minuscule .0005" over bullet diameter. Same thing with the new PRC cartridges (6.5 and .300)

While I've never been a wagoneer myself, I'n not obstinate enough to deny the truth when I see something that works. And the Creedmoor cartridges work, primarily because they were designed from the ground up to do so. I don't own a Creedmoor and don't have plans to do so, I am building a 6.5PRC for both long range target and hunting.

Full disclosure - I have a full custom in 6.5-06AI. Interarms Mark X action, 24" Krieger match barrel, Timney trigger. I call it my "600-yard clay pigeon shooter" because it does so well at that. My girls love to shoot it because recoil is mild with the laminate stock and heavy barrel. I expect my 6.5PRC to shoot equally well, but it won't be quite able to match the 6.5-06AI in terms of velocity.

If you are head-in-the-sand stuck on not getting a 6.5 Creedmoor, I'd recommend a 6mm CM or 6.5 PRC.

charlie b
07-12-2019, 08:59 AM
You don't mention what range.

Out to 600m (and sometimes further) my .223 does really well with heavier bullets. It only fails me (or I fail it) at longer ranges.

The .308 does respond well to longer barrels if you load for it, especially when using heavier bullets or you want that extra 100 or 200fps with a lighter bullet.

I use those two calibers and am very happy with their performance. But, age is catching up with me so the recoil with the .308, even with a heavy rifle, starts to bother me after 10 or 20 rounds. I am looking at 6.5 and 6mm choices as well.

Here are some good guides of different target cartridges.
https://www.accurateshooter.com/

6mmBR_Shooter
07-12-2019, 09:07 AM
#1. Do you reload? I wasn't able to tell from your post. That certainly makes a huge difference regarding the availability of factory ammo for certain cartridges.
#2. Is this a pure target rifle or might you hunt with it? Once again, makes a difference regarding barrel length and contour. A 20lb F Class rifle with a 32" barrel is not fun to carry in the woods or even to a stand.
#3. How much recoil do you want? The 7WSM you mention is going to recoil significantly more than a 6mm BR.
#4. How far do you plan to shoot? 7WSM seems silly for a shorter range target rifle.

I'm a huge 6mm BR fan, and they are very popular for 300 out to 1000 yards in Benchrest, F-Class, PRS, etc. They shoot a wide weight of bullets depending on your application and the cartridge design is very efficient and accurate. Barrel life is also very very long.

If you're sold on 7mm, a straight 284 is a great choice. They are also winning their share of 1000 yard Benchrest and F-Class matches, and are easy to tune. The heaviest long range bullets will likely require single loading in a 284, not sure about the short magnums you mentioned. Those short mags though will require changing your bolt head, and likely your magazine follower.

This is an older article, but the information is still solid: https://www.6mmbr.com/7mm284.html

celltech
07-12-2019, 09:12 AM
I will throw out the oddball suggestion.... 243 AI

BB68
07-12-2019, 10:35 AM
Isacpotatoes, Im with you on new "wizbang" contraptions, but I did buy one (6.5CM) last winter and am quite impressed. Now I think my next will be 6 CM.

TXRoadlizard
07-12-2019, 12:48 PM
[QUOTE=isacpotatoes;458115] I'm open to getting a hunting rifle chambered in 7mm-08, but for now my .270 should do.

I've hunted deer with a .270 for about 5-years. I switched to .270 from 7mm Mag after shooting a buddy's rifle. I know 7mm-08 is an effective round, but I can't imagine switching away from .270. It is a deer killer for sure, and it is cheap to feed. Best of luck with whatever you choose!

isacpotatoes
07-16-2019, 02:08 AM
Just to clarify , this new chambering would be for a target/ tactical rifle. Not a bench rest by any means, but in field with distances that change.

I am sort of reconsidering 6.5; looking at 260 AI, and 260 AI Match. The problem there is that I'd have to rely on firearm forming. My understanding is you can still shoot a standard cartridge in an Ackley Improved chamber. I don't know if that is also true for a Match AI as opposed to just AI.

Part of my choices are contingent on barrel selection from certain makers. Criterion seems to be well respected, but they don't offer any WSM/SAUMs in 7mm. Maybe the 7mm-08 performance is good enough with enough velocity out of a longer barrel?

Thoughts?



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charlie b
07-16-2019, 07:12 AM
Because I do not have a large budget, one of the main considerations for me is barrel life. It is the other reason I chose .223 and .308 for my two rifles. The other reason was availability of brass.

Since I know I will be replacing a barrel in the next year or two I have been looking at similar cartridges. The 6x47 is very tempting. Long barrel life seems to be one of the characteristics of this one. The 6.5x47 seems to be similar. But, since Lapua came out with small rifle primer cases for the 6 and 6.5 CM there are now four (in my mind) to choose from. The .260 and 6.5x55 (or .243 Win) are better choices (IMHO) if you want to push velocity more.

Keep in mind that this is armchair information. I have never owned any of them, just doing preliminary research like you. The great thing about the current fads is the large number of target shooters out there these days, especially the F classes and PRS folks. Tons of information on all of these cartridges. I have shot a 6.5CM and I like the lower recoil over my heavy bullet .308 loads, which is why I am considering the 6 or 6.5 for my next barrel.

6mmBR_Shooter
07-16-2019, 11:55 AM
According to guys in the know on SnipersHide (https://forum.snipershide.com/threads/creedmoor-barrel-life.6394874/), match-accurate 6mm Creedmoor barrel life is around 1500 rounds, and 6.5 Creedmoor is closer to 2500 rounds. Brass availability is good for both, as is bullet and powder selection. None of the Creedmoor cartridges are setting the F Class world on fire, but they're doing well in PRS.

6mm BR and its derivatives are also well represented in PRS and other competitions (https://precisionrifleblog.com/2018/12/14/rifle-caliber/), and a regular 6mm BR has an accurate barrel life out to 3-4,000. My 6BR is a 28" Criterion 8 twist barrel and with a mild 30 grains of RE15 launches Nosler 105 Custom Comps at 2750fps. This is a slow load but will print in the .2s all day long, and has performed very well for me out to 800 yards. Premium brass is affordable, 6mm bullets are cheaper than 6.5s and 308s, and it uses significantly less powder than the Creedmoor family.

If you were dead set on a 7mm, I'd go with the 284. It'll do everything you want. If you were not set on a 7mm, I'd do a 6mm BR. You honestly can't do wrong with either one.

varget204
07-16-2019, 04:32 PM
Look at the 6mm, 6 BR,6BRX,6BRDX,[6 BRA] 6 dasher,6 creedmoor.The 6 BRA holds the current world records at 600 and 1000 yards.The 6's are flatter,faster,and less recoil,cheaper to load

tobnpr
07-16-2019, 05:28 PM
Just to clarify , this new chambering would be for a target/ tactical rifle. Not a bench rest by any means, but in field with distances that change.

Maybe the 7mm-08 performance is good enough with enough velocity out of a longer barrel?

Thoughts?

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I don't see where you mentioned the max range you're shooting.
This is THE most important variable. At a few hundred yards, it makes no difference (except maybe, if you're shooting in a hurricane) whether it's a .308 or most anything else in terms of external ballistics. For most "capable" chamberings, extend that out to about 600 yards. Your .308 is more than capable of shooting better than you can at that distance.

It's beyond 600 yards that external ballistics -drop, drift, and velocity- really start to matter as the bullets begin to slow dramatically and therefore, are much more subject to external influences.

Among others (including a .260 match chamber), my 7-08 is an absolute go-to for our current max distance available which is 600. 7mm is a great compromise round- better ballistic coefficients than the .30 cals- and better barrel life than the 6.5's. I just bought a .284 Win reamer with no-turn neck for Lapua brass which will fill the space between the 7-08 and the .338 Lapua for me. This has been a favorite long-range chambering for many years- still the most widely used chambering for Team USA F-Class; in fact, most every one of their rifles is chambered in 7mm of one flavor or another.

That should put to rest your question of "suitability" of 7mm boolits...

http://www.usfclass.com/what-we-use

As to whether the 7-08 performance is "good enough" for you- that depends on A) range to target, and B) how proficient a marksman you are - or want to be.

Don't overthink it, again- unless you're regularly shooting at 700-1000 and beyond it's not critical. It's not a hunting application so energy at target is meaningless.

As far as the .260, it's the same as the 6.5 Creedmoor you eschew (maybe can be loaded a bit hotter due to case capacity), and the 6 Creedmoor is the same as the old .243.

It's MARKETING.

Coyote_Hunter
07-16-2019, 06:12 PM
isacpotatoes -

Fire-forming cases is not a difficult task, nor does it need to even be a chore. I have a 6.5-06AI, for which I fire-form .25-06 brass. The fire-form loads are very, very accurate, much to my surprise.

I use a Hornady max load of H4831SC under a 140g bullet. Velocity loss is abut 5% compared to the Hornady data. But they are gentle shooters and so accurate I don't mind.

isacpotatoes
07-16-2019, 07:41 PM
I don't see where you mentioned the max range you're shooting.
This is THE most important variable. At a few hundred yards, it makes no difference (except maybe, if you're shooting in a hurricane) whether it's a .308 or most anything else in terms of external ballistics. For most "capable" chamberings, extend that out to about 600 yards. Your .308 is more than capable of shooting better than you can at that distance.

It's beyond 600 yards that external ballistics -drop, drift, and velocity- really start to matter as the bullets begin to slow dramatically and therefore, are much more subject to external influences.

Among others (including a .260 match chamber), my 7-08 is an absolute go-to for our current max distance available which is 600. 7mm is a great compromise round- better ballistic coefficients than the .30 cals- and better barrel life than the 6.5's. I just bought a .284 Win reamer with no-turn neck for Lapua brass which will fill the space between the 7-08 and the .338 Lapua for me. This has been a favorite long-range chambering for many years- still the most widely used chambering for Team USA F-Class; in fact, most every one of their rifles is chambered in 7mm of one flavor or another.

That should put to rest your question of "suitability" of 7mm boolits...

http://www.usfclass.com/what-we-use

As to whether the 7-08 performance is "good enough" for you- that depends on A) range to target, and B) how proficient a marksman you are - or want to be.

Don't overthink it, again- unless you're regularly shooting at 700-1000 and beyond it's not critical. It's not a hunting application so energy at target is meaningless.

As far as the .260, it's the same as the 6.5 Creedmoor you eschew (maybe can be loaded a bit hotter due to case capacity), and the 6 Creedmoor is the same as the old .243.

It's MARKETING.

Thank you for the insight. Range is not a factor for me; in the sense that the available range is somewhere under 1,400yds at a friend's property.

This new chambering will be for once I'm done shooting up my 308, and the brass is no longer viable for reloading. Some where around 2,500 rounds from my calculations. As I've stated, I'm currently reloading for my 270; I will for my 308 once I've shot all my factory ammo in 308.

To answer the marksmanship question; I'm beginner to intermediate for sure. I have about 5yrs of shooting under my belt, with the last 3 having been with bolt guns, most of which are sub-9lbs (I didn't have a scope for a year on the Savage, but just picked up a Nikon X1000).

That's what's nice about the Savage 10FCP-SR, is the weight. With scope and bipod it'll be in the neighborhood of 12lbs. I dry fire at every range session on the bench. A heavier rifle will hide the bs tendencies shooters have too.

I'm curious about the 7WSM, SAUM, & Shedhane cartridges, buuut brass will be more affordable and available in 7mm-08. That's where barrel length helps the 7mm-08 or any short action right cartridge right? Magnums obviously need more in order to utilize all the powder.

Thoughts on optimal barrel length?
24"-26"? Perhaps 24" with a brake?

I very much agree that marketing is taking place with calibers like 6.5 PRC or 6mm creedmoor when 243 Win and others are still viable. It is cool that the 6.5 PRC fits in a short action tho.


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Coyote_Hunter
07-16-2019, 09:07 PM
It is not just marketing. As I stated before, the Creedmoor and PRC cartridges have SAAMI specs for the cartridge and case that are held to tighter tolerances. This means you stand a greater chance of getting a barrel that is accurate with a wider variety of loads than most other cartridges. SIL has two 6.5 CM rifles, both very accurate with the variety of loads he has tried. Coincidence? I think not.

FWIW, both of Hornady's 6.5PRC loads (143g ELD-X and 147g ELD-M) maintain supersonic velocity out past your 1400yd range. The ELD-M load stretches it to 1800 yards.

I've looked at a lot of cartridges for my build (long action), including the 6.5 PRC, 26 Nosler, .270 Win, .270 WSM, .280 AI, 28 Nosler and .300PRC. Since my goal was a long range shooter with a light rifle with minimal recoil, the 6.5PRC was the top contender. While I have not ordered the barrel yet (and may not do so until after Jan 1, 2020), the 6.5 PRC remains at the top of the list for a lot of reasons, even though it would be a short-action cartridge in a long action. (Kind of like my Savage .22-250 when I had it.) One reason is I believe it will be well accepted and supported by manufacturers and ammo costs will be far less than some of the others I considered. While I reload, the rifle will likely be handed down to someone that does not.