Home Forums Hunting & Shooting Ask The Gunwriters 7mm-08 - 120gr. vs. 140gr. re-visited

280 - My subject should have been 120 vs 140, rather than pitting the 120 BT to the 140 BT, as the latter is not my fav as it has been fairly fragile, at least in the past - though not sure if the bullets I used long ago are made the same today, probably so in the 140.

No doubt, your AI seemed about 100fps faster than an AI would be expected in a 26" I would fathom. Twist may have been slower perhaps? I now the coating may have affected pressures on the XLC as well. I don't sweat 100-150 fps in anything unless I am say down at 2400-2500 mv to begin with...ie. handgun rounds.

Thanks for sharing the info on the 120 vs 140 AB on deer. My greater concern w/the 120 is more on using it on game larger than deer. I have much respect for Steve and don't dispute his experience. Yet he himself discussed how tough it is for ANY bullet to get thru say a 30lb sack of wet grass in an elk's stomach and avoiding shots, as I would, but if you ONLY had one chance and had to bust a shoulder knuckle or go from the hind end, I'd feel better with more than the 120 BT. I drove a 150 PT lengthwise from a 270, thru a Mulie and would feel pretty good on most any elk shots at normal ranges. That was around 275ish. It has a good SD and as we know expansion stops at the H. It shed the nose and the jacket was intact, reversing back after the base tumbled fwd as it finished in the hind end (frontal neck facing).

What would be great to see is a 7mm bullet test across the board, as the one BC Steve did on the 6.5s. Different bullets, but you can see some 30-40% increase in penetration looking at the 120 BT vs. a 120-130 Barnes, or 140 AB, again, those in 6.5mm.

For deer I could take either the 120 BT or any 140, but on elk, I'd rather a 140 AB, PT, or Barnes...just feel it would be a little insurance if you were only left w/a bad shot angle that was still viable. Bullet choice no doubt is subjective.

Thanks Bman.

There's some misinfo on this thread and others regarding the 7mm 120gNBT.

Many moons ago I was told by Steve Timm via phone the 120grNBT is no slouch. I called him a few times after he wrote an article on the 7-08AI (SGLC). Later I sectioned the 120gr and a 140gr and posted the picture on the 'fire in '03 after Eremicus had some questions about the 120grNBT. That picture has been posted everywhere on the web since then. Around the same time I filed both bullets I spoke with Chub Eastman who used to work for Nosler . He told me the 120, 140 and 150 7mm NBTs are all made from the same jacket, they simply cut the jacket shorter from the top for each bullet weight.

Hey DZ, Tell me about the 7mm 120gr (picture removed from thread)

JimF Thread from 2006



The jackets are the same, the 120 is thicker (in the nose area) because the jacket walls are tapered to begin with so the 120 winds up with a thicker jacket near the tip when compared to a 140 or 150gr NBTs. A few yrs ago I did a penetration test from my 7-08:

Nosler 120grBT vs 140grBT Penetration Test

I've slayed big game critters with all (3) 7mm NBTs and see no reason to use the 120grNBT unless you are recoil sensitive or your rifle won't shoot the heavier bullets. I can still watch the hit thru the scope with the 7-08/140 combo. I personally have a hunch the 150grNBT over RS Hunter would make a great LR load, it might launch at 2800fps from some 22" 7-08 bbls.

For even better penetration try the 140grNPT in a 7-08, it will go clean thru lengthwise on most black bears.

MtnHtr

+1......and other animals as well. Very good killer. Jerks the rug from under northern bucks.Can't recover one.

Wondering out loud what barrel lengths and loads are being used to get the velocities I am seeing here with either 120's or 140's (?) I have not experienced them myself with 140's but maybe I have not experimented enough.

Yeah... it's a speed-fest on this thread!

Bobin, I used Varget and IMR4064 for most my loads in 139-140, and typically 120s over Varget. 1 gr over book max IIRC, 45/140 and 47/120 comes to mind, but I'd have to check notes, RP brass, primers flat, but no cratering or sticky extraction.

Again, in my chopped 700s, the 21" avg. 3050-3100 w/120s and the 139/140s did 2900-2960. Had a 20" M70 carbine, it did 2850 using that load under 139.

Speed kills as JOC and WBY noted, but so does mass at modest fps, as Elmer preferred. Many ways to skin a cat as they say.

I simply challenge hunters to run the #s on all loads and decide, rather than looking at mere mv.

Fast MV is often chosen to add range/reach or PBR, yet look above, the 140 matches the speed of the 120 in typical loads in std. chambered 7/08s, at 300 yds and beyond the 140 overtakes it, MORE bullet, and increasing differential impact speeds. Something to consider IMO.

Again, as I started the thread, never said the 120s are not good or don't work, Steve proved it and I respect him and his R&D, but again, he used an SGLC or AI which on avg. shows about 200 fps in his rifle, than the speeds you will commonly see in non - AI rifles. You will see the AI 120 load reaches just over 80 yds, before dropping to the 3050 which is a good average you see in std. bbl std. chamber rifles. SO a shot at 380 using an AI would be like one at 300yd w/a Saami, purely on impact speed using the 120 NBT.

I have no doubt Steve could have dropped all his game using a good 139-140 had that been his choice. Do however consider his 80 yd advantage if your planning on shooting an elk at 400 yds using a 7/08 Saami at say 3050mv/120 BT.

In the end driving bullets thru vitals kill. Deer are not armour plated, but elk as Steve tells, are another challenge when it comes to penetration, depending on shot presentation.

That very reason is why some opt for far more bullet i.e. a 30 or 338 cal when after elk, using high SD well constructed bullets. No doubt they offer a margin of insurance if one needs or wants to take a poor shot angle, yet they are probably more likely to drive stem to stern IMHO than any 120 BT.

I had a hind end shot on an elk in timber, but had no cow tag, under 100 yds, I had 100% Confidence my 225 PT in my 338/06 would have plowed thru all to get to THRU vitals w/destruction, yet no license = no shot.

Another hunt I had an elk broadside at 30 yds using my M70 carbine w/139/2850 and had 100% confidence had it been a legal bull...it's brown tine was not the legal 5" in that area of CO so I had to pass, but that elk would have died quick had it been legal and both lungs wrecked w/that 139. YET, had I encountered the scenario on the Cow above, I'd passed if I had a license, unless I could have shot the neck.

A Barnes or Partition would have changed my attitude using that 7/08 had I been faced w/a poor shot angle. That cow btw never turned any other angle before disappearing into timber.

Bullet choice is subjective yet I think consideration on game hunted, impact speeds at the max/range expected, and KNOWING a bullets general behavior on varying degrees of hardness of target and depth of penetration required on different game, is ultimately what guides one in making a good bullet selection for an upcoming hunt, as well as HOW the hunter will decide to shoot or pass on a given shot presentation.

MtnHtr - good link/test/info - thanks.

Shoot well guys. Enjoyed the posts.

Oh, btw Jeff, I bet a 120 TSX or TTSX in a 7RM, SAUM, or WSM would be a wicked beast

Horse hockey...

Umm, John, I just ran two loads through the chronograph two days ago, they were 140's in a 7X57. One shot each so keep that in mind. 52 g. of H414 with a PRVI 140 g. showed 2956 fps., 51 g. of H205 with a 140 Nosler PT showed 2917 fps, I have run the Noslers faster with more H205 so the 51 g. load is my "throttled back" load. BUT -- My rifle has a long throat and a Douglas barrel that seems "fast" compared to another 7X57 I compared it to years ago. So I think 2950 with 140's is safely doable in some rifles.

On the other hand, the long list of posts with great accuracy and high velocity in 7mm-08's with Big Game and Nosler 120 BTs does not seem to work in my 7X57. To me the pressures seem high and the accuracy was less than my normal 140 g. loads. Each rifle is unique. YMMV.

Doesn't the 7X57 have more case capacity than the 7-08?

Yes it does by about 2 grains from what I can read and I factored that into my loads when trying to approximate 7mm-08 data. But I work up to from below in 1/2g. increments; checking velocity and signs of pressure at each step. (note: my 7X57 has a 22" barrel)

L = 7-08/140NPT R = 7x57/175


MtnHtr

It's all good as far as I'm concerned. I've shot 140 TSX in my Tikka 7mm-08 for a long time and have had no failures on antelope, deer, elk, and bison. Always used 42.5 grains Varget and mag primer(2850 fps). I'm transitioning over to a 150 grain Win Power Point and Ramshot Hunter this year.

I jumped on the 120 bandwagon because of Steve. Bought several hundred 120 seconds and my lil 708 likes them. They work very well. Had the 140's been on sale that day I might be shooting/loving 140's....grin

CKW,

The 7x57 has 3 grains more case capacity than the 7-08, that is a significant difference.

When you get 2950+ with a 7/08 -22" bbl. and don't get hard bolt lifts and flattened primers let me know...

Max. loads with a 22" bbl. shooting any 140 is around 2885 fps and that's pushing the ragged edge IME.

If there is a way to get one with a 22" tube to 2950+ safely, I have never heard of it.

Best,

jm

More like 2800 fps from my 22" rifle but there's powders I haven't tried.

65BR: yeah, KodiakHunter has a new-brass load that gets 3500 fps with the 120 TSX from a 24" 7WSM. Yowsa!

Hi Jeff, I can safely get 2865 pushing a 140 AB using Big Game and magnum primers. This rifle has a 22" bbl.

John, all I was trying to say is that there is enough variation in different rifles that some may achieve velocities that others cannot. I do not have a 7mm-08 (don't need one as I have a perfectly satisfactory 7X57). I use 2 grains more capacity for 7X57 with 7mm-08 data (i.e. Ramshot powders) where there are no loads listed for the 7X57 with that powder as a way to cautiously work up loads for my rifle.

I do have two 257 Roberts with 22" barrels and one almost always gives 100 fps or more with a wide variety of loads including factory loads than the other. The higher velocity rifle shows pressure signs earlier than does the slower one -- sometimes even with factory loads or commonly suggested 257 loads. This does not seem unusual.

As mentioned, my 7X57 with Big Game starts to show pressure with the 120 Nosler BT before I reach book loads for 7mm-08s. But with H414 it easily digests loads at or above most book loads for the 7X57.

My 30-06 does not come close to book values or to what many others report theirs develop. But it has a 20.5" barrel and should get less velocity but the difference is closer to 200 fps than 100 fps.

It seems that each rifle is unique.

My dad gets about 2875 out of a 20" remington with 139's and H4350.

It seems that the 120BT is fairly stiff, and slower opening.

What is a good bullet ~120gr with quicker opening characteristics for Coyote and smaller varmints ?

Using 45/Varget (1gr over book max) my 21" 700s (my former rifles were 700 BDL/Varmint and BDL/SS) clocked 2900-2960.

My 20" M70 did only 2850 using a 139. Most all loads used RP brass, though would run WW today, holds a tad more = perhaps 1-1.5 and is better brass IMHO.

Yep, each rifle shoots different. JM - my primers were always flat, but never cratered or pierced and no sticky lift.

BTW, ALL my loads were partial sized. I could back off 1 gr and not change the outcome of a hunt Probably the right thing to do.

I'd guess a good custom tube might give a little more on avg. due to less friction, but again all bbls are different. Usually customs are slicker IME, but bore specs can be tighter/looser depending on individual bbl.

As to the 7x57, yes holds more, but seems a tad less efficient design, but if you load it to the same pressure as a 7/08, it should match or best a 7/08, esp. with heavier bullets.

I recall I guy using HOT loads one day back in college, he used a 700 classic 22" and putting out 140s at 3K and change. I personally would not load like he did - but he was a preacher so maybe felt he had luck on his side

The 120 hornady vmax