Why don't we see more 7mm-08 builds? My wife shoots a 7mm-08 and it is a tack driver and it has very little recoil.
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7mm-08
- Thread starter Direct_Fire
- Start date
good question! I can't think of a good reason. I'd much prefer it to a .308, but I think so many go that route because military and police use it and it's been around awhile. it has more options for reloading, but the 7mm-08 has a fair amount of options too. It is definitely an underutilized round.
I'm also stunned how few people choose the 708, going instead with a 6.5 Creed or 260. The 708 is easier on the barrel, drifts a little less in the wind (unless you use an uber-bullet in the 6.5) and smacks the steel (or dirt if you miss) quite a bit harder than the 6.5s.
If you run energy calculations on what you can get out of a 6mm-08, 6.5mm-08, 7mm-08, .308 and .338-08, you'll see the 7mm version is the "most efficient", meaning you can create the highest amount of muzzle energy with the 7mm variant.
It's trajectory/drift makes its 308 parent look like "the fat kid at the track meet" with very little disadvantage in barrel life.
Recoil? If you run the numbers and compare bullet momentum (at the muzzle, which is the root of recoil) across the X-08 lineup of cartridges, you'll see the 7mm variant with a 162@2800 has *just* about as much as the .308 with a 175@2650. When loaded for long rang target shooting, the 7mm-08 does not have a recoil advantage over a traditionally loaded 308. Load 208 amaxs in the 308 and run them hard at 2500 or 2550, and that's a different story.... Load hunting-type 140s into the 708 and yes, it will have significantly less recoil than a tradionally loaded 308.
If you run energy calculations on what you can get out of a 6mm-08, 6.5mm-08, 7mm-08, .308 and .338-08, you'll see the 7mm version is the "most efficient", meaning you can create the highest amount of muzzle energy with the 7mm variant.
It's trajectory/drift makes its 308 parent look like "the fat kid at the track meet" with very little disadvantage in barrel life.
Recoil? If you run the numbers and compare bullet momentum (at the muzzle, which is the root of recoil) across the X-08 lineup of cartridges, you'll see the 7mm variant with a 162@2800 has *just* about as much as the .308 with a 175@2650. When loaded for long rang target shooting, the 7mm-08 does not have a recoil advantage over a traditionally loaded 308. Load 208 amaxs in the 308 and run them hard at 2500 or 2550, and that's a different story.... Load hunting-type 140s into the 708 and yes, it will have significantly less recoil than a tradionally loaded 308.
I'm mostly a hunter so am a huge fan of the 7mm-08. In fact I kinda feel naked unless I have a couple in the safe at all times. Here is my newest that just arrived about a month ago. A really handy rig that I hope sees lots of use this year.
For long distance shooting the 6mm and 6.5mm have less recoil, less drop, and damn near the same windage. Also the 7mm-08 has very few options for factory match ammo - not a problem for the reloader but a consideration. For hunting and energy on target the 7mm is definitely the top pick, but energy/hunting isn't at the top of most competition shooters list.
Also just to throw it out there. If you are considering the 7mm-08 the 7CM is worth a review.
Keep your powder dry,
Goat
Also just to throw it out there. If you are considering the 7mm-08 the 7CM is worth a review.
Keep your powder dry,
Goat
I understand the love for 6mm and 6.5 tactical match guys but for a awesome hunting rifle that can also go to the range and hold its own. The 7-08 is a win win for them guys.
Thanks for the heads up guys. I am a big KISS method guy when it comes to choosing calibers for rifles and pistols. I like to keep everything shooting about the same round to make things easier. I had not thought about the lack of match ammo for the 708, but that is a big deal.
Thanks for the heads up guys. I am a big KISS method guy when it comes to choosing calibers for rifles and pistols. I like to keep everything shooting about the same round to make things easier. I had not thought about the lack of match ammo for the 708, but that is a big deal.
The 7-08 is an excellent caliber for a reloader of you intend to shoot it in competitions, and also good for the hunter since there's plenty of factory hunting rounds that'll take down most north american game. Like you all said though the lack of factory competition ammo doesn't do the 7-08 any favors.
Trued Rem 700
#3 contour Brux, 1-9" twist, fluted & finished @ 22.5"
McMillan Classic Edge in brown & black speckle, red recoil 1", ADL
Ti flute on bolt and Camfire bolt knob by Kampfeld
Graphite black Cerekote
Jewell trigger, Talleys.
Weight with scope is 7 lbs 4 ozs and balance is about perfect IMHO
Smith - Jon Beanland @ Beanland Custom Rifles,
What is the math supporting this statement? Just not sure what the statement means, "most efficient"? The 243 and 260 are pretty darn efficient...
As I wrote in my post which you quoted, "most efficient" the way I used it means you can create the highest amount of muzzle energy with the 7mm variant of the X-08 case.
In fact, the 6mm and 6.5mm offerings are the *least* efficient way to turn chemical energy inherent to smokeless powder into kinetic energy of a projectile using an X-08 case.
We can argue all day about bullets, barrel lengths, power charges, SAAMI pressure, and what energy levels are achievable....but here's a little arithimetic:
Kinetic energy = .5 * mass * velocity * velocity
For example:
243 Winchester, 115gr DTAC, 3100fps
(.5 * 115gr * 3100fps * 3100fps) / 7000gr/lb / 32.2 fps^2 = 2452 lb*ft
Repeating this calculation for various X-08 cartridges we use for long range target shooting:
243Win, 115 DTAC, 3100fps - 2452 lb*ft
260Rem, 140amax, 2850fps - 2523 lb*ft
708Rem, 162amax, 2800fps - 2817 lb*ft
308Win, 175smk, 2675fps - 2778 lb*ft
Again, we can argue about nuances all day about how so-and-so is getting 3400fps from their 115dtac in a 243 (2950 lb*ft by the way) because they are using a duplex charge of bullseye and H1000 and have a 38" barrel....
I'm pretty sure I assigned reasonable velocities to each cartridge, assuming reasonable and typical powder charges and barrel lengths.
Copy, good post. I would buy that explanation for a dollar! Thanks for taking the time to explain that out nicely. Makes a good case for 7-08 as best choice of the -08 family for a hunting application.
Since the amount of powder consumed is all pretty similar between all members of the -08 family, I don't think the conclusion would change one bit. If you were comparing the 7-08 to a big magnum that metric would be useful. For example: 180gr 7mm at 2950 = 3475ftlbs at muzzle/62gr of powder consumed= 56ftlbs/gr of powder consumed. 7-08's 162gr at 2800 = 2817ftlbs/45gr of powder = 63ftlbs/gr of powder consumed.
I like 7-08 threads so tag.
I just started to explore one myself. H4350 162 Amax and to pressure with no real speed. Turbos"s note at 2800 looks like 280 speed. I have seen other posts with better speeds than I have gotten so far, Im down at 2600 - 2650 still.
I just started to explore one myself. H4350 162 Amax and to pressure with no real speed. Turbos"s note at 2800 looks like 280 speed. I have seen other posts with better speeds than I have gotten so far, Im down at 2600 - 2650 still.
If I didn't have personal experience with 162s in 708, I'd never believe it could sling them at 2800.
But they usually will.
~44.5-46.5gr h4350, 162amax, 2.825" (more is better) and a 24"+ barrel will get you 2750-2850fps depending on specifics.
My buddys 26" CBI Savage did 2825 with 46gr before melonite. After melonite that load shows pressure so he backed off to 45.5gr, and gets 2780.
Same friend did ladders this weekend with 180 hybrids (2.825") and didn't hit pressure @ 44.5gr. Don't know velocity but I'll bet its moving pretty good.
A fellow currently selling a 708 barrel for an AI claims 2725 with 175smk.
Lots of folks in the reloading depot report 2750-2850 with 44.5-46.5 h4350
708 is the best variant of the '08 case!
Even better in magazines that accommodate 2.900"+ COAL!
i had GAP build me a 7-08 simply cuz i could. no other real reason been contemplating punching it out to a 7saum but haven't even had time to shoot it yet, lol.
As far as the efficiency goes the smaller bullets may have higher efficiency at longer range due to a higher ballistic coefficient. I still like the round though, I have one that i've taken a lot of deer with.
What 6 and 6.5 bullet(s) are you referring to?
Litz verified 7mm BCs:
162amax - .600
175smk - .639
180smk - .65
180 hybrid - .67
175XLD - .66
explain how the superior BC of 6s and 6.5s is better at range...?
ETA: I'd argue the higher velocity of the 6s and 6.5 (to a lesser extent) makes them a little better for midrange shooting because they're flatter.
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kinetic energy= i/2(mass)*(velocity^2)
ballistic coefficient is how drag affects a bullet. the 6.5 will generally be affected less by air resistance so will maintain more of it's velocity. if you recalculate with the energy at say 800 yards the masses will stay the same, both velocities will have went down but the 6.5 velocity will have gone down less. i haven't ran teh actual number, but i speculate the 6.5 will have surpassed the 7 mm. another important thing is to distinguish between energy and momentum. i believe someone had mentioned momentum.
momentum= mass*velocity.
notice mass and velocity have the same affect on momentum whereas velocity as twice the effect of mass on energy because it is essentially used twice in the calculation (velocity^2=velocity*velocity)
Tag for future reference.Trued Rem 700
#3 contour Brux, 1-9" twist, fluted & finished @ 22.5"
McMillan Classic Edge in brown & black speckle, red recoil 1", ADL
Ti flute on bolt and Camfire bolt knob by Kampfeld
Graphite black Cerekote
Jewell trigger, Talleys.
Weight with scope is 7 lbs 4 ozs and balance is about perfect IMHO
Smith - Jon Beanland @ Beanland Custom Rifles,
Nice build in a light package
hopefully that helped a little? if not i can go over it with actual numbers when i have more time. I should add that i may wrongfully used the word "smaller" i meant smaller diameter bullets, using a smaller diameter bullet of the same mass will naturally have less air resistance.
The 7-08 has the longest effective range off the -08 variants, also.
I decided on .260 because of recoil; I was warned by some experienced Hiders that 7-08 recoil is equal to or more than .308 when loaded up.
I'm hoping that the rifle I'm building with a 24" M40 profile barrel in a McRees and a Little Jimmy brake will recoil more like .223 than .308.
Joe
I decided on .260 because of recoil; I was warned by some experienced Hiders that 7-08 recoil is equal to or more than .308 when loaded up.
I'm hoping that the rifle I'm building with a 24" M40 profile barrel in a McRees and a Little Jimmy brake will recoil more like .223 than .308.
Joe
Turbo, H4350 @ >2.900, 162 Amax, new Winchester brass and 210m=
45.0= 2600
45.5= 2650
It would be a hoot if my Chrony is a pos. I am going to take these out and see what my actual come ups' are.
My Chrony put factory 69 FGGM @ <2800 but I got steel@1000yds with 49 min. 100yd. zero. NF doing the cypherin.
Sure looks like the chrony is slow and good news for my 7-08.
I knew I loved this.
45.0= 2600
45.5= 2650
It would be a hoot if my Chrony is a pos. I am going to take these out and see what my actual come ups' are.
My Chrony put factory 69 FGGM @ <2800 but I got steel@1000yds with 49 min. 100yd. zero. NF doing the cypherin.
Sure looks like the chrony is slow and good news for my 7-08.
I knew I loved this.
I see what you were saying now. I thought you were directly comparing the BC of the 6/6.5/7mm bullets.
In a side by side comparison of the 162 amax and the 140 VLD of retained velocity and energy both starting at 2800fps (JBM calc - Litz BC);
At 500y 162 = 2093fps/1575ft-lbs -- 140 = 2105fps/1378ft-lbs
At 1000y 162 = 1490fps/798ft-lbs -- 140 = 1511fps/710ft-lbs
Do the math and that gives the 162 71.19% retained velocity and 50.66% retained energy, and the 140 has 71.78% retained velocity and 51.52% retained energy.
Conclusion: The 140 VLD beats the 162 amax in velocity retention by .59% and energy retention by .86%, but either way you are running wind and elevation almost identically (2-4 inches) with either bullet out to 1000y. Also even though the 7mm is .86% less efficient than the 140 it still has more energy at any given range than the 140.
Good point on recoil. The 708 has every bit as much as a 308 when both are loaded for long range. Subjectively, it is mg feeling the 708 "feels" like more recoil in the same way a 40 "feels" like more than a 45.
A 260 is a solid step down on recoil.
All comes down to what you need the rifle to do. If punching paper/steel out to 1K is all the rifle will be doing then the .243 is hard to beat with the same drop/drift as the 6.5/7mm, but with the added feature of minimal recoil. If hunting gets added to the equation energy on target becomes a much more important number, and as was mentioned earlier the 7mm (of the X-08 cases) has the numbers. The 6.5 is a middle ground between the 6/7mm in regards to recoil and energy. Also to consider is barrel life 6<6.5<7.
I shoot a 708 and love the round so much that I am building an 18"er also (at the smith right now and should be back in 2 weeks)
Here is my load I shoot comps with
26" Rock Cut 5r 8.5 Twist
Shoots damn good, had a 4" group at 1k with and does pretty good on paper. No pressure signs at all and runs like a champ.
162amax
46gr H4350
210m
Win brass
2.875" Mag length
Velocity 2780fps
Here is what I found with Varget
44.5 2940fps (not nice on brass)
44.0 2910fps (still not nice on brass)
43.5 2875fps (still flatten primers)
But for my 18"er I am going to test with Varget. It will be made with the same barrel as above. I am pretty sure I can get a safe enough load past 2700fps as this is not a comp gun it is mainly for hunting and playing around with.
The 708 is great round but it does kick just as much as a 308. I have shot a few 6CM and 243. That round is a great comp round. My buddy is shooting a 243 with a 105amax going over 3200fps. That thing still hammers at 1k which is pretty much all you need in most comps in my area. With a brake it feels like a dang 223 to shoot.
Here is my load I shoot comps with
26" Rock Cut 5r 8.5 Twist
Shoots damn good, had a 4" group at 1k with and does pretty good on paper. No pressure signs at all and runs like a champ.
162amax
46gr H4350
210m
Win brass
2.875" Mag length
Velocity 2780fps
Here is what I found with Varget
44.5 2940fps (not nice on brass)
44.0 2910fps (still not nice on brass)
43.5 2875fps (still flatten primers)
But for my 18"er I am going to test with Varget. It will be made with the same barrel as above. I am pretty sure I can get a safe enough load past 2700fps as this is not a comp gun it is mainly for hunting and playing around with.
The 708 is great round but it does kick just as much as a 308. I have shot a few 6CM and 243. That round is a great comp round. My buddy is shooting a 243 with a 105amax going over 3200fps. That thing still hammers at 1k which is pretty much all you need in most comps in my area. With a brake it feels like a dang 223 to shoot.
7mm08 is an awesome chambering. Accurate, easy to load for and great bbl life. I'm getting roughly 2750 with 162s in a 22" bbl.
Recoil is certainly there. I put a brake on mine - made it a pud to shoot.
Recoil is certainly there. I put a brake on mine - made it a pud to shoot.
I am having two built right now for my boys
Trued Rem 700 LH
#4 contour Brux, 1-9" twist, finished @ 24"
Manners MCS-EH2 one midnight one Gap
Graphite black Cerekote
Smith - Brad and Keith Johns @ PCR
Brad also built my 7 mag it is pictured in the photo he did of the twins the one in the back.
Trued Rem 700 LH
#4 contour Brux, 1-9" twist, finished @ 24"
Manners MCS-EH2 one midnight one Gap
Graphite black Cerekote
Smith - Brad and Keith Johns @ PCR
Brad also built my 7 mag it is pictured in the photo he did of the twins the one in the back.
Well I read the whole thing.
Makes my head hurt with all that match and shit.
Here is what I know from experience. If I want to win I shoot my 7MM08. I have the most confidence in it.
If I want to kill something(mostly white tail) I pick up my 7MM08.
If I just want to have lots of fun banging the long range steel I ........... well you know ^
Yes, I have a 308 and a 260 and a 6.5CM. But when the distance gets past 600 I want that 7MM08 snugged up to my shoulder.
Makes my head hurt with all that match and shit.
Here is what I know from experience. If I want to win I shoot my 7MM08. I have the most confidence in it.
If I want to kill something(mostly white tail) I pick up my 7MM08.
If I just want to have lots of fun banging the long range steel I ........... well you know ^
Yes, I have a 308 and a 260 and a 6.5CM. But when the distance gets past 600 I want that 7MM08 snugged up to my shoulder.
Load is 42.1gr of Varget Win LRP with a OAL of 2.890". Barrel is a Kreiger 1:10 hunter contour finished at 22".
I feel the barrel is a bit fast as I was expecting velocity in the 2800-2875fps mark but was very happy with the results.
I also delved into the 7-08 category. Will post a pic when I get it back from the smith. Mostly hunting rifle and went off the beaten path to a model 70. It is getting accurized currently. Stock hunting rifle loaded with 140 gr Berger reliable to 875 for me
The advantage of the 7-08 continues to increase over the other cartridges listed the farther out you go.
Joe
Working up load for my latest 7MM08, a Bartlien chambered by GAP for my AIAW. I had been working with H4350 and 168SMK since that combo worked so well in my other gun but I tried some Alliant 2000-MR yesterday. While velocity is about 80 FPS lower than the loads I have with H4350 it shows great accuracy. Also, when I run comparisons in JBM the 2000-MR load will still out last the 175 SMK in 308 at 1000 yards.
Anyone else using 2000-MR in the 7M08?
Anyone else using 2000-MR in the 7M08?
I've kind of wondered why you don't see many of this caliber being built either. Seems like I always hear a lot of good things concerning the caliber. I'm currently having a 7mm-08 built right now, going to be used mostly for hunting.
Specs:
Defiance Rebel
Bartlein #3 1-9 twist finishing either at 22 or 23"
Jewel trigger
McMillan game scout
R&D DBM
I was really tempted to go with a 308, but did the 7mm since I'll use it mostly for hunting.
Specs:
Defiance Rebel
Bartlein #3 1-9 twist finishing either at 22 or 23"
Jewel trigger
McMillan game scout
R&D DBM
I was really tempted to go with a 308, but did the 7mm since I'll use it mostly for hunting.
I have a 7-08 that Turbo has actually shot. The thing is a hammer and every once in a while I get a wild hair and think about selling but I just can't do it. It's old faithful and the caliber's ability to buck wind is huge. I have come to the conclusion it will always be my main rifle for most competitions. Only complaint currently is that brass is a PAIN to hund down at the momment. If we could only keep the 260 guys from stealing our brass we'd be set.
BTW I run the 162 BTHP at 2780fps out of a 26" McGowen 1 in 8 twist. I believe the 8 twist is ideal because it can stabolize anything all the way up to the 180s.
Good luck,
Merritt
BTW I run the 162 BTHP at 2780fps out of a 26" McGowen 1 in 8 twist. I believe the 8 twist is ideal because it can stabolize anything all the way up to the 180s.
Good luck,
Merritt
Nice rigs guy I love the 7mm08 its basically what I learned to shoot with after the .22 of course. I took my first 8 deer with one. Till I was 16 and moved up to a 300 WM. We have 2 a savage 10 and a rem model 7 both shoot awesome and have taken a lot of deer without any problems. All the kids in my family have taken their first deer with one of the two.
Reloder 17 blokes !
I'm getting 2800fps with 162gr Amaxs out of a 22" Barrel. COAL 2.875"
I've worked up to 46gr in my rifle without pressure issues. You'll need a powder drop tube or vibrate the cases to settle in the powder and it will be a compressed load.
My hunting load is: 162gr Amax
45gr RL17
Lapua 260 Rem brass expanded up to 7mm
CCI BR2 Primers
COAL: 2.875"
Speed: 2740fps
Reloder 19 also works well if you can cram enough into the case.
I'm getting 2800fps with 162gr Amaxs out of a 22" Barrel. COAL 2.875"
I've worked up to 46gr in my rifle without pressure issues. You'll need a powder drop tube or vibrate the cases to settle in the powder and it will be a compressed load.
My hunting load is: 162gr Amax
45gr RL17
Lapua 260 Rem brass expanded up to 7mm
CCI BR2 Primers
COAL: 2.875"
Speed: 2740fps
Reloder 19 also works well if you can cram enough into the case.
