Help Picking a 7mm
- Thread starter Seeking_Coyotes
- Start date
I go larger capacity for two basic reasons when hunting:
One, it extends the bullet's useable distance, as I must make sure I do not shoot further than the minimum impact velocity of said bullet.
Second, lower the amount of wind drift.
For a LR or ultra LR hunting rig, I do not have barrel life in mind or ammo cost. I am looking for a race horse that gives me the desired impact velocity for said bullet at my chosen max distance.
It will not be a gun that I give a ton of range time in either load development or just practice. A high quality build with a good barrel typically will not take that much to get it shooting good. I always need 1/2 MOA or better for a 3-shot group (hunting gun not a comp rig), and I almost always work toward 1/4 or better MOA at 100 yards. Confirm my short range choice by grouping at 500-600 yards in your case.
I will practice with it enough to get its drops confirmed, and then one or two shots per 100 yards starting around 700 yards out to and beyond 1200 yards from field positions.
I will use other guns to practice with the majority of the time.
In my loading, I will be following typical BR reloading protocols too. I am looking for LR benchrest accurate hunting rig.
Something that is capable of sub half groups at 1K in ideal conditions, but useable in the field.
One, it extends the bullet's useable distance, as I must make sure I do not shoot further than the minimum impact velocity of said bullet.
Second, lower the amount of wind drift.
For a LR or ultra LR hunting rig, I do not have barrel life in mind or ammo cost. I am looking for a race horse that gives me the desired impact velocity for said bullet at my chosen max distance.
It will not be a gun that I give a ton of range time in either load development or just practice. A high quality build with a good barrel typically will not take that much to get it shooting good. I always need 1/2 MOA or better for a 3-shot group (hunting gun not a comp rig), and I almost always work toward 1/4 or better MOA at 100 yards. Confirm my short range choice by grouping at 500-600 yards in your case.
I will practice with it enough to get its drops confirmed, and then one or two shots per 100 yards starting around 700 yards out to and beyond 1200 yards from field positions.
I will use other guns to practice with the majority of the time.
In my loading, I will be following typical BR reloading protocols too. I am looking for LR benchrest accurate hunting rig.
Something that is capable of sub half groups at 1K in ideal conditions, but useable in the field.
Wouldn't the .284 Win have alot of kick? That is the one drawback I see and I am thinking I'd like a gun that doesnt have alot of kick. However, I don't see myself as ever being a guy would could shoot good enough to shoot at 1,000 yards.
OK...so funny story (at least to me).
My hunting partner lives about an hour and half from me. Not alot of critters his way so we hunt on the many spots I have around my place. We do very good on fox and fair on coyotes. So we decide to do some groundhog hunting yesterday. Now the attitude at least with me is this is a pretty simple deal to find groundhogs to shoot. Go out to one of numerous farms, sit in a chair, and look around as far as you can see with good spotting scopes and binocs, etc. Expect a bunch of shooting. Well, I am a lousy groundhog guide because in the past I could pretty much find them anywhere. We sat in fields for about twelve hours and no shots. Don't know what happeded around here but it is like they are gone? So shortly before packing up my buddy said he spoted one. I wanted him to shoot but he only had his .17 Remington as his old .243 is at Douglass getting a .243 Ackley Impoved barrel installed. He ranged the hot at 700 yards!!! I looked at my new turret noticing it stops at 600 yards
. Hold over an inch or two on the 600 setting and miss. Just kinda relay this story because I think it demonstrates that you can never have enough gun for long distance shooting as I learned yesterday.
My hunting partner lives about an hour and half from me. Not alot of critters his way so we hunt on the many spots I have around my place. We do very good on fox and fair on coyotes. So we decide to do some groundhog hunting yesterday. Now the attitude at least with me is this is a pretty simple deal to find groundhogs to shoot. Go out to one of numerous farms, sit in a chair, and look around as far as you can see with good spotting scopes and binocs, etc. Expect a bunch of shooting. Well, I am a lousy groundhog guide because in the past I could pretty much find them anywhere. We sat in fields for about twelve hours and no shots. Don't know what happeded around here but it is like they are gone? So shortly before packing up my buddy said he spoted one. I wanted him to shoot but he only had his .17 Remington as his old .243 is at Douglass getting a .243 Ackley Impoved barrel installed. He ranged the hot at 700 yards!!! I looked at my new turret noticing it stops at 600 yards
. Hold over an inch or two on the 600 setting and miss. Just kinda relay this story because I think it demonstrates that you can never have enough gun for long distance shooting as I learned yesterday.Seeking_Coyotes said:
Have a look at the 284 Win section of the 7mm cartridge guides elsewhere on this website:
http://www.accurateshooter.com/cartridge-guides/7mm/#284win
Winchester developed its 284 way back in 1963 to give approximately .280 Rem performance, but in short-action rifles thereby determining its overall length at 2.8-inches. To achieve that, it's a 'rebated case' design using a smaller diameter rear end, case-head and extractor groove as per the 0.473-inch dia. .308 Win / .30-06 etc, but with a fatter, large capacity body above - same as the belted magnums. It was also ahead of its time in having a relatively low case taper and 35-deg shoulder angle producing a short, fat case with sharp shoulders which has since become 'in' largely thanks to small precision cartridge designs like the BRs and PPCs.
There were two problems with the cartridge 50 years ago. It was only chambered in the Winchester Model 88 levergun, which although reckoned as the best ever lever-action made by Winchester wasn't a success with buyers, and also the Model 1100 semi-auto hunting rifles - no bolt actions. Secondly, 7mm bullets are long in relation to their weight, and the factory 2.750" COAL effectively limited the .284 to 150gn maximum, and even here the bullet had to be seated VERY deep in the case. It really asked for a long-action turnbolt rifle and 3.00" or longer length. The Model 88 and the cartridge didn't prosper, but the case attracted wildcatters who used it for all manner of long-range match and hunting cartridges, the 6.5-284 Norma eventually coming out of this activity. As a result, Winchester never entirely dropped the cartridge, but only occasionally made production runs, maybe only unprimed brass.
Eventually, Norma Precision recognised the widespread use of the 6.5mm wildcat in long-range match shooting and introduced a regularised version in 2000, the CIP max COAL listed as 82.00mm / 3.228-inch). 6.5-284 was / is a very effective long-range match / hunting number, still widely used, but its barrel life of 800-1,300 rounds put a lot of people off it, F-Class etc users needing a new barrel every season (at least!), and meanwhile the bullet companies were introducing new high-BC sevens in the 175 and 180gn range. By returning to the original 7mm version of the design, shooters got very good long-range accuracy, less wind drift than with the 6.5mm version, and nearly double the barrel life - hence the popularity of the .284 Win, but chambered / throated for long COALs and heavy bullets. The only downside is a modest increase in recoil.
There was a parallel move after 2000 by US deerhunters who were into having custom rifles built. With factory Norma and Lapua brass now easily available and easily necked-up to 7mm, they had rifles built as .284 LT (long-throat) on long actions and were in advance of the target shooters here.
In terms of capacity, the 284 case lies as follows (grains weight water held by a case with no bullet in it):
7mm-08 ............... 55gn
284 Win ............... 66gn
280 Rem .............. 68gn
280 AI ................. 74gn
7mm Rem SAUM .. 73gn
7mm Rem Mag ..... 82gn
7mm STW ............ 97gn
So, it's close to the .280 Rem (also growing in popularity for custom long-range rifles) as was devised by Winchester that half-century ago, but in the desired shorter / fatter case shape. (I'm not convinced it makes that much difference - if any - but the available brass is very good quality.)
With a CIP PMax of 4,400 BAR / 63,817 psi, that's a fully high-pressure modern number giving very strongly constructed brass, and it is a more efficient design ballistically than larger capacity numbers such as the short magnums, and much more so the 7mm Rem Magnum and STW that burn a great deal more powder for relatively modest velocity gains. The optimum case size for 7mm in this regard lies in the 284 Win to 7mm SAUM / WSM region and 7mm Remington Magnum and larger are getting into the over-bore-capacity zone.
Wow...that was amazing. You are very smart about this case and have really helped me understand it much better and why so many are moving to this case.
Could you tell me how the kick would compare to a 30.06?
What is the barrell life in shots?
Am I correct is buying a 7mm bullet for the caliber?
Could you tell me how the kick would compare to a 30.06?
What is the barrell life in shots?
Am I correct is buying a 7mm bullet for the caliber?
holstil
Silver $$ Contributor
7mm=284
I'm shooting an improved version on a low node and my 284 shoots like a puppy fart'n biscuit crumbs with the brake on it compared to other larger 7mm's I've shot.
I was burning 6.5-284's in less than 1000rds. Once the quality high BC bullets came out and brakes on HV were OK'd by IBS, it was a no brainer for me to switch. I'm getting about twice the barrel life with the 284 and a lot more with the 08.
Hard to beat the 7-08 for an all around one gun. Cost of 7mm bullets might be a drawback. I think they're swaged with platinum cores
Laurie could prolly write for Wiki about any cartridge.
Jim
I'm shooting an improved version on a low node and my 284 shoots like a puppy fart'n biscuit crumbs with the brake on it compared to other larger 7mm's I've shot.
I was burning 6.5-284's in less than 1000rds. Once the quality high BC bullets came out and brakes on HV were OK'd by IBS, it was a no brainer for me to switch. I'm getting about twice the barrel life with the 284 and a lot more with the 08.
Hard to beat the 7-08 for an all around one gun. Cost of 7mm bullets might be a drawback. I think they're swaged with platinum cores
Laurie could prolly write for Wiki about any cartridge.
Jim
All right...you guys are way smarter and more experienced than I am. Thank you for you patience with me. This switch barrel thing sounds interesting. So help my little brain.
I have a new Savage Model 10 in .243. Can I just buy a drop in barrel and a new scope and bingo I have two guns? Or, do I need to do something mechancial to change barrels?
I am interested, I think, from what you guys are saying, in the .260, .284, and 7mm-08.
I have a new Savage Model 10 in .243. Can I just buy a drop in barrel and a new scope and bingo I have two guns? Or, do I need to do something mechancial to change barrels?
I am interested, I think, from what you guys are saying, in the .260, .284, and 7mm-08.
Not exactly. And the first extra barrel costs more than the rest as you have to buy the tools.
But here's an approximate cost breakdown. And I will use Jim Briggs and Criterion barrels in my examples.
Criterion barrel in you choice of length, contour, twist, and any chambering that Criterion offers.
Here are the choices for 6, 6.5 and 7mm barrels.
243 (6mm) Caliber - 6 BR Norma - 6X47 Lapua - 6mm Dasher - 6 XC - 243 Win - 243 AI
264 (6.5mm) Caliber - 6.5X47 Lapua - 6.5 Creedmoor - 260 Rem - 260 AI - 6.5X284 Norma
284 (7mm) Caliber - 280 Rem - 284 Win - 7mm Rem Mag - 7mm RSAUM
The barrel cost is ~$350 shipped and ready to screw on your action.
Action wrench and barrel nut wrench - under $100
Go gauge - ~$35
Basically, you remove your scope & base, remove the stock. Use the tools to break the barrel nut loose. Unscrew the barrel currently in use from your action. Move the nut and recoil lug over to the new barrel. With the go gauge chambered, screw the new barrel on your action until it contacts the go gauge, open the bolt, tighten the barrel nut. (I tighten to 40 ft/lbs.) Check to see if bolt still closes. Add a layer of scotch tape to the rear of the go gauge and if you did real well, the bolt won't close now. If it takes two layers of tape, you are still OK. Return barreled action to stock, put scope base and scope back on. Or if switching from a varmint barrel to a big game barrel, you might want to switch scopes as well.
I swap barrel two to four times a year. It is no big deal and can be cone on the kitchen table.
But here's an approximate cost breakdown. And I will use Jim Briggs and Criterion barrels in my examples.
Criterion barrel in you choice of length, contour, twist, and any chambering that Criterion offers.
Here are the choices for 6, 6.5 and 7mm barrels.
243 (6mm) Caliber - 6 BR Norma - 6X47 Lapua - 6mm Dasher - 6 XC - 243 Win - 243 AI
264 (6.5mm) Caliber - 6.5X47 Lapua - 6.5 Creedmoor - 260 Rem - 260 AI - 6.5X284 Norma
284 (7mm) Caliber - 280 Rem - 284 Win - 7mm Rem Mag - 7mm RSAUM
The barrel cost is ~$350 shipped and ready to screw on your action.
Action wrench and barrel nut wrench - under $100
Go gauge - ~$35
Basically, you remove your scope & base, remove the stock. Use the tools to break the barrel nut loose. Unscrew the barrel currently in use from your action. Move the nut and recoil lug over to the new barrel. With the go gauge chambered, screw the new barrel on your action until it contacts the go gauge, open the bolt, tighten the barrel nut. (I tighten to 40 ft/lbs.) Check to see if bolt still closes. Add a layer of scotch tape to the rear of the go gauge and if you did real well, the bolt won't close now. If it takes two layers of tape, you are still OK. Return barreled action to stock, put scope base and scope back on. Or if switching from a varmint barrel to a big game barrel, you might want to switch scopes as well.
I swap barrel two to four times a year. It is no big deal and can be cone on the kitchen table.
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