I've been loading 7mm-08 for three different rifles for a few years now. I'm now starting to develop loads for my new Browning BAR 7mm-08 and need you to help me think think this through. In the past, I've basically been a "Heavier for caliber" kind of guy, thinking this benefited penetration. (I like two holes) Now it doesn't seem to me that weight plays near as big a role as it use to and my focus is shifting toward accuracy above all else. (Please straighten me out if I need it :-) )

Given all of the new bullets on the market today, for a given caliber, what role does bullet weight now play in the scheme of things? It seems that now there are lighter weight bullets that now can do what it took heaver bullets to do in the past.

For example, the 7MM 120gr Nosler Ballistic Tip is one of the highly lauded bullets on these forums, with many many examples of excellent accuracy, deep penetration and deadly performance. At the same time there are much heaver 7MM bullets that accomplish the same thing.

So.... given equal accuracy, trajectory (under 300 yds), and performance.. what would lead you to pick a lighter vs heaver bullet, or vice versa? What's the trade off?

Looking forward to hearing your thoughts!
firstshot

If performance will be the same and you're happy with it then accuracy of the heavy light bullet in your rifle.

I still don't think you can really beat the 140BT/139IL/140PT trio in the 7-08 - if you like variety.

Well, if you're limiting yourself to 300 yards, then there really is no reason to go with the heavier rounds. The benefit of the heavier round is it extends the range and keeps its energy at longer distances. If you want to extend your range, then the heavier rounds are your best choice.

Thanks Rusty815

The absolutely most accurate bullet I've loaded in 3 different 7mm-08's is the Hornady 154gr Round Nose. They clover leaf at 100 yds if I do my part and they are absolutely devistating on Deer and Hogs. I'm getting 2,830 fps muzzle velocity out of them with my 22" barreled BAR and H414. Sighted in 1" high at 100, I'm 2" low at 200 and 5 1/2" low at 250 which is no prob for where I hunt here in central Texas.

I will stick with this as my main hunting load for now, but I love to reload and will do my due diligence working up other loads for my new BAR with focus bing on accuracy.

Thanks again for the input!!
firstshot

if everything else is the same, recoil will be noticeably less with the lighter bullet.

More speed is more better on deer sized critters.

FirstShot -

That is the coolest animated avatar ever. Looks like a CT NPTG, except the partition is a bit far back. Surprised I've never seen/noticed it before.

Back to the original topic -

Old school thinking was a higher SD (weight) yields greater penetration.

I'd be real interested in a test of TSX or TTSX that looked at penetration vs weight for a given cartridge. Let's say .30-06 with a 110, 130, 150, 165 and 180 gr bullet, just to see if the conventional thinking still pans out.

Nothing has changed. Only the hype. The little additional velocity that the lighter bullets gives you does little for lethalness nor trajectory. A well kept secret is the 154gr round nosed bullet in the 7-08. It is a HAMMER. And out to 300 yards, it gives nothing away to a spitzer for trajectory.

It still comes down to inertia, weight X velocity. To my mind penetration isn't the major factor so the bullet design and BC doesn't matter that much upon impact. Bigger IS better!

While the 154 gr round nose is a good bullet in the 7mm's it's gotten a little difficult to get them. I believe that's another one that hornady has dropped. Building a load on an obsolete bullet is maybe not the best use of time. Unless one has good stockpile of them.

You are not thinking clearly about why the lighter mono-metals are so superior to your round nose bullet. Stick a 120 grainer and that round nose bullet into an STW at maximum velocity to see what the hype is all about. You hit even a deer at full throttle and it will disintegrate. I know from personal experience. You hit an elk in the shoulder at fifty yards with a velocity of 3,550 feet per second and you will get a dead elk and an exit wound.

They are getting hard to get. Called Hornady today and was told that the 7mm 154 RN's have in fact been discontinued. So... I started my stockpile by ordering 400 of them.

At <300 Yds the 154gr RN gives up nothing on trajectory; however, they drop like a stone after that. I use a Ballistic Plex reticle & sighted in .5" high at 100 here is what it looks like. With the B-Plex aim points I'm basically dead on out to 300 Yds


I've been hunting with these for several years and terminal performance has been exceptional. A bunch of dead dear and hogs, most of which were DRT. I have never recovered one of these. All shots have been complete pass throughs. Got two pigs with one shot weekend before last. Pig#2 moved into path of Pig#1 just as I fired. Bullet went through the head of Pig#2 and then through neck of Pig #1.

I am working up some "Longer" range loads though. Starting with the 140gr Accubond. Am also ordering some of the 120gr NBT's (which I belive I can push to about 3,200 FPS) so I can see first hand what all the small/fast "hype" is about. :-)

I'll stick with the 154 RN "Hammer of Thor" as my main hunting load, but it is good to have alternatives.

Thanks to all four your input
firstshot

Hey Ringman.... we're talking 7mm-08 velocities. I can't speak for the 120BTs as I've never shot them and don't know how they would hold up, but the Hdy 154RN definitely was not designed to be shot at STW velocites and I totally agree with you that it would totally disintegrate at those speeds. It works great as intended though!

Regards
firstshot

What Klikatarik said! powdr

I'm thinking quite clearly thank you. I don't believe the 154gr RN was designed for velocities in excess of 3000fps. But what it does, it does well. FWIW, I've never shot an elk with a mono bullet nor have I shot an elk with the bullet going in excess of 3000fps (at the muzzle). But, guess what, in every case, I got a dead elk with two holes in him. I'm sure the non-shooting fellows hanging around the water cooler are really impressed with the velocity of your whizzum.

Assuming your preface is true and you are not looking for agreement with a preconceived notion.

Two holes are a very notable characteristic of all the copper bullets. Remarkably so compared to cup and core bullets.

That penetration combined with equally notable killing ability across the board for the copper bullets of significantly less weight is an indication that weight plays a very different role today. Simply put, those little light copper bullets going fast consistently do an outstanding job. For example, there is little to no difference between an 85 grain TSX out of a .270 and 150 grain TSX out of a 270 inside 300 yards when it comes to shooting deer. Having put enough 80/85 grain copper bullets through deer with a .243 I know they'll work just fine on bigger things and still make two holes. I literally cannot see any difference in the holes an 80/85 grain TSX/TTSX makes through deer and the holes a 150-168 grain TSX/TTSX out of a 300 WM makes. They go all the way through even when very long penetration distance is necessary and they tear up what they go through.

In 7mm leaving range beyond 300 yards out of the equation there is no earthly reason other than hunting in 30 MPH or more winds to want anything heavier than the 120 grain TTSX for deer. If a 90/95 grain TTSX was available, it'd be even better.

As long as you can hold a bullet together, more speed kills better. I have yet to see a copper bullet come undone and I have used them at speeds of 3600 FPS and shot deer at 25 feet at those speeds. I do know of one bullet that lost at least one petal like that. I cannot say that I did not lose petals on any other bullets, but I have no evidence of that happening and I have examined a lot of deer shot with copper bullets. Some of those deer had a lot of bone crunched.

The fact that the people shooting deer with .224 cal 53 grain bullets don't recover bullets any more readily than anyone else and the "holes pictures" they post look the same as much larger calibers tells me that the answer to your question is the only role left for bullet weight is to buck wind a little better and carry speed a little longer. Inside 300 yards, those are much, much smaller considerations in most hunting.

I have to find the quote, but the late Finn Aagaard once said something along the lines of that once you have sufficient weight to penetrate the vitals any more weight adds zero to killing power.
Finn always made a lot of sense.

Lou

stillbeeman,

You posted you didn't understand all the hype about the light bullets. I tried to help you understand. It sound like you sitll don't.

If it were me, I'd just find the most accurate bullet between 120-154grn, and then hunt with it. The one you end up with may be softer or harder than the rest, but it'll be your most accurate projectile, and will work on deer if you place your shots.

I like b-tips and interlocks for deer myself, and have always had great accuracy and performance from them.

I�m not trying to prove any preconceived notion. Just want to clearly understand the role bullet weight for penetration in light of the new �tougher� bullet types on the market today (i.e. bonded / TTSX etc).


For a given velocity and bullet design, doesn�t bullet weight impact the amount of penetration?

bullet BC might make a difference in penetration, since a heavy square bullet wouldn't penetrate but a light long skinny one would.

Here I think we're getting into the age old and often debated topic of terminal performance . . . small/fast vs big/slow :-)

Good point bgalt. Sectional density definitely plays a role in penetration but I'm not sure how much when staying within a given caliber. SD for 7mm 120BT is .213 and SD for 7mm 154RN is .273. Thats a 28% increase in SD but not sure how much difference in penetration that factor alone would make.

Can anyone shed some light on the relevance of sectional density to penetration?

A lot of factors play a role in how much penetration you would get, but I think energy on the target and bullet construction and characteristics are the biggest factors as to how much penetration you get. A bullet that retains its weight will get more penetration than one that sheds it, I was recently reading on some tests done with the 95gr. TTSX and 120gr. SST in a 6.8, the SST would break apart as it hit the target resulting in it penetrating only a few inches whereas the TTSX expanded but retained all its weight, resulting in more penetration. I believe Bonded bullets also have good penetration, but not as much as monolithic bullets such as the TSX or TTSX.

Hey Rusty . . . Been hearing a lot about the TSX / TTSX. Is there any trade off with rate of expansion? In other words do they open as quickly as cup & core or bonded "tipped" bullets? Would they open as quick at 7MM-08 impact velocities? Say 2,200 - 2,700 fps impact velocities?

firstshot

Yeah.....it ain't worth shidt without good bullet construction.


Whoever made the comment on the square bullet not penetrating.....you would not ever want to bet any sizeable cash on that one...its a proven fact that flat meplat bullets penetrate FAR more than pointy,high BC bullets in heavy game.....talk to any truly experienced handgun hunter about that one.Or notice the trend with todays super solids to use a flatter meplat for deep penetration.There's a reason.

Hustling through air is not the same as hustling through game flesh....a fact lost on many.

Thats all I use for hunting. I use the 140gr. TTSX and 139gr. GMX (Hornady's version of the TTSX), run em at around 2760fps, and have only recovered one GMX. The deer was shot at 130 yards at the shoulder and went diagonally through the deer, ended up lodged in the skin on the rear right of the deer. It expanded perfectly and to about a bit over a half an inch wide, it retained 98% of its weight, and the deer dropped right in its tracks. I like Monolithic bullets because of their deep penetration and they don't ruin nearly as much meat. They are also speed demons, which means the faster you run em, the better they perform, not to say they don't perform well at lower velocities, the 95gr. TTSX test I alluded to shot the TTSX down to 1900fps and it still expanded perfectly, Barnes says minimum expansion velocity is 1700fps, and it seems to be pretty close to the truth. I run the 80gr. TTSX in my 243 at 3450fps and that thing is a hammer, I've never shot one within 400 yards that wasn't expanded perfectly.


Only real drawback is that monolithic bullets are expensive, and bonded bullets such as the Nosler accubond or Hornady Interbond perform almost as good, and are a bit cheaper. If you don't mind the price I highly recommend them, if not, look for just about any bonded bullet if penetration is a concern of yours.

Yep. The penetration concerns of today are a bit silly since the vast majority of game hunted in the U.S. is deer or smaller. Dunno why so many think they need bullets for an African safari. My experience has shown high penetration bullets result in deer running a bit further and very few bang flops. YMMV.

I used the Hornady 7mm 139 grain SP's boosted to 2950+ fps. It did work well on deer but it wasn't robust enough to penetrate well when it struck deer at under 100 yards. I was getting a lot of shot up meat, and no exit wound. I went to a 150 gr. Partition, so that I could rely on performance at any range encountered, get two holes and cut back on shot up venison. Been completely happy with them. I use the 140TBBC in .270, and about any 165 gr. in 30 cal. under .300 Win Mag.- then I go up to a 180 gr. AB or Partition.
YMMV

Comparing apples to apples (TSX/TTSX to TSX/TTSX) there is really little consideration of penetration. Even a 53 grain TSX will penetrate a deer virtually every time from most angles. Once you get to 6mm monos they are even more so prone to make two holes.

Yes, penetration is proportional to weight. but... when you have well more penetration capability than is needed the additional weight contributes little to killing ability.

A bullet carrying enough mass and speed to penetrate through will cavitate better. Cup and core bullets epend a huge amount of energy deconstructing the bullet. In plain english, the energy that goes into deconstructing a cup and core bullet is unavailable to create damage. That high velocity transit and the subsequent cavitation channel is responsible for a lot of the "kill". No one that I know of has yet done an analysis of how much energy goes into deconstructing cup and core bullets and what that does comparatively to the damage done when almost all that energy s conserved. My observations tend to support greater total damage to the animal particularly when a lot of bone is in the path. Cup and cores tend to come undone faster hitting bone than monos, and monos oftimes don't seem to notice bone.

A 130ttsx will retain almost 100 percent whereas a 150 cup and core will lose 50 percent..... See why a lighter mono will still penetrate more than a heavier bullet?

I think that is a big part of it Sako75, the heaviest bullet at the end of the job(after pentration), is the one that will travel further.

When a cup and core 130grn bullet loses 50% of it's weight, it ends up 65grns. When an 85grn mono bullet keeps all of it's weight, it ends up 85grn, having kept all of the momentum it started with.

So even though the 130grn started out heavier, it's the bullet that ends heavier that should penetrait the furthest.

The other thing is meplat or profile. If a bullet mushrooms very wide, it is contacting and pushing a lot more mass around in the target than a controlled expansion bullet that doesn't create a wide profile/meplat.


I'm still a cup and core fan.

I shoot a 7x57. I'm a traditionalist with that rifle and don't shoot polytips in it. But mainly I shoot 150Partitions @2725. I've figgured out that a medium weight bullet ie 150s in 7mm and 165s in 30cal. They shoot a little slower, penetrate well, and don't destrow as much meat. FWIW I use the 150BTs in my 280 and will tell you that they are tough. In my limited experience with them the 150bt at impact speeds 2200fps-2600fps is very much the same as the Partition. In fact I'd use them in my 7x57 if I wasn't such a traditionalist. capt david

Part of the reason that weight for weight barnes bullets penetrate further is that the front of the bullet expands only so far.
Their is less resistance when the frontal region is small, some bonded bullets retain allot of their weight but if the frontal region is large their is more resistance and they will not penetrate as far because of this. The partition bullet is made to shed its frontal region relatively quick, so that the base can penetrate further. I would be willing to bet that a bonded bullet that has a large frontal region of the same caliber and weight will not penetrate as far as a partition bullet. When going at magnum velocities (3000fps +) bonded bullets and dependent upon velocity and bullet construction most other bullets will penetrate just as far if not further than the bullets at magnum velocities. The one for sure exception to this is monolithic, and fmj bullets. I have had a bonded bullet impact at 3000 fps + penetrate less than a cup and core bullet at 308 win/30-06 velocities.

I with 'ya. I'm a relative neophyte to loading for my 7-08 but so far have an extremely accurate 120BT load, and another for the 140 Nosler AB. Chasing big mule deer really turns my crank. If I were going out the door chasing one today with the 7-08 I'd take the 140 AB load, even though the 120 BT load kills the crap out of whitetails. It's just the way my feeble mind works I guess.

First Shot,

I've been waiting for someone to comment on the velocity you are quoting but so far no one has.

You state 2830 fps for a 154 gr. bullet out of a 22" barrel.

My 5th edition Nosler manual doesn't give figures for a 154 gr. since they do not make that weight. With H414 powder for a 150 gr. bullet they give a max. of 2800 fps but this is with a 26" barrel. For a 160 they give a max. of 2650 fps. Splitting the difference it suggests a max. of 2725 fps from a 26" barrel. It seems to me your load must be on the hot side.

I checked an old Hornady manual I have but it didn't list any loads with H414 with the 154 gr. bullet.

At one time I had a 22" barreled 7/08. Mostly I used 140 grainers in it. To obtain any kind of accuracy I had to keep velocity well below 2800 fps.

Just curiosity on my part.

Jim

Hey Jim

I'm using a new "The Complete Reloading Manual for the 7mm-08 Remington" (Copyright 2011)
which does show H414 for the 154 RN. The intro for the Hornady section shows that they were using a 24" barrel with a 1-9 twist. The load chart shows a max load of 48.3 gr H414 in the 2,800 fps column. The velocity columns are in 100 fps increments and for the 154 RN 2,800 is the highest. Their 24" barrel could have been pushing anywhere between 2,800 and 2,899 with this load and would still show up in the 2,800 FPS colum.

My BAR has a 22" barrel 1-10 twist and I chronographed with my F1 Shooting Chrony. 6 shots @ 48.3gr actually averaged 2,828 with no preasure signs. Among other powder amounts chronyed were 46.7gr @ 2,724 and 47.5 @ 2,770.

I checked my load notes for my Rem 700 MTN LSS 22" barrel and this bullet/powder shows 47.5gr @ 2,736 and 48.0gr @ 2,771.

So the BAR is showing 2,770 @ 47.5gr VS. the MTN LSS 2,736 @ 47.5gr. I'm not sure why this is.

I just loaded up a new batch @ 47.5gr for the BAR. Since that is where I got the best accuracy in the Mtn LSS, I figured I would start there with the BAR. I haven't shot these yet but will definitely chronograph them when I do and will report back.

firstshot

First Shot,

It sounds as though you have one of those elusive "fast" barrels. I wasn't being critical just curious based on my earlier experience with a 7/08. A bullet that has worked well for me in 7mm is the Hornady 154 gr. spire point. This has been especially good in my 7 Rem magnum. In other calibers round nose bullets have worked well, such as the 180 gr. RN in .30 caliber.

Jim

JIM . . NP.. after looking at my load notes difference between the BAR and the MTN LSS I was a little concerned too, thinking I might have gotten the BAR reloads into the lands causing more pressure and increased velocity. I drug out the stony point and remeasured both the rifle and the new box I just reloaded. I'm definitely NOT into the lands with OGIV on both at 2.682.

My range is still a mud hole from the recent rains we had, but as soon is it drys out I'll chrono this new batch. Would be nice to have one of those "fast barrels"