Home Forums Hunting & Shooting Ask The Gunwriters 6.5mm 120BT's vs 7mm 120 BT's

Now we talking a bunch of hats...

DF

https://www.24hourcampfire.com/ubbthreads/gallery/80/full/74422.jpeg
https://www.24hourcampfire.com/ubbthreads/gallery/80/full/74423.jpeg
So, Im not sure if I got these (2) pics to load or not. If they did upload it’s a pic of my .5” 3 shot group100yds from the tikka 260 shooting factory federal premium 120 grain ballistic tip. Second pic is the exit wound from the 120 grain bt on a smallish MS 90 lb yearling. It obviously did the job but I liked em wayyyy better before the water jug test.
Big Ed

I have just taken possession of 4 boxes of 120 gr. Ballistic Tips to run in a 6.5 Grendel. At 2500 fps I expect good expansion and penetration from them along with fine accuracy. For years I avoided using Ballistic Tips because of the bad press they got early on but when that turned around I found them great bullets. A favorite is the 150 gr. .284 diameter Ballistic Tip. This bullet will do a heck of a lot of work out of a medium 7MM rifle.

Why? That deer pic exit looks about perfect.

I agree with JG about velocity. C&C bullets generally have a designed velocity window. If one keeps that in mind, optimal terminal performance will be the reward.

Monos are said to have no velocity ceiling. I've had issues with that. IME, very low S.D. mono's at hyper-velocity can result in less than optimal terminal performance on WT's. My one time experience with the 80 TTSX out of my .240 at 3,600 fps caused a huge superficial blast effect, then penciled thru the chest for a slow kill. Too much energy expanded too quick. With higher S.D. bullets, not as big an issue. Seems S.D. below .2 can be a red flag if pushed super fast. That's just my observation, would appreciate input on that.

DF

Theory: The 80 hit so hard and fast it blew its petals right away. Then you had a small diameter solid that made it through. A bullet of the same diameter and construction but higher SD will be heavier, and hence moving slower. Upon impact it will retain its petals farther into, if not all the way through, the penetration and hence make a better wound channel.

Some don't like blood and gore photos, but this one shows the huge, gaping hole in the chest wall. I've posted it before. There was a small thru and thru chest wound, doe ran 100 yds,; we had to find her with flashlights in the woods at night.

I switched the .240 to 100 gr. NPT's which it seems to like. It turned out to be the most accurate bullet in that gun, an HS Precision SPL in a Hunters Edge. I've shot half MOA groups at 400, in fact, one three shot group was 1.7".

It's my observation about the < .2 S.D. being a potential cut off point for hyper velocity W.T. mono loads. So, even monos may have a practical velocity ceiling, especially the low S.D. ones.

DF

jg I am happy with that exit hole it produced that time but that was no shoulder or spine bones hit and don't remember about ribs. I guess in a perfect world where you hit exactly where you aim and the deer doesn't move at trigger pull and buck/doe fever doesn't ht and you snatch the trigger they are as perfect a whitetail bullet as ever created. but,and there is always a but, I am trying to prepare for the not so perfect scenario where dealing with a bigger deer or bad angle or pooched shot or take your pick of issues. I'm not writng the 120 bt off the list as its very accurate and obviously deadly in my 260 rem tikka. I would just feel better about a little tougher i.e. partition/accubond bullet at the moment to cover my 6 if I make a blunder of the shot. heck to change calibers my sons tikka 7mm-08 shooting the hornady 120 sst did better in the water test by far than the 120 bt. the 120 7mm held together,core stayed into and locked to the cup/jacket, and looked a lot like a accubond after the recovery in the 4th milk jug. the 125 partition made it to the 6th milk jug and the 130 accubond was lodged between the 5th and 6th jug.
Big Ed

Good deal whitearrow. Hard to argue with choosing a partition.....the perfect big game bullet IMO.

that we agree on jg. if a partition will shoot accurately in your particular rifle its all you will ever need for big game imho. I just hope my tikka t3 like partitions as well as bt's and accubonds. that group I posted was .5" and it shoots 3 130 grain accubonds into .7"@100 yds with regularity. my fingers are crossed on the partition but I can shoot the accubonds if need be. I wanted to like the 120 bt sooooo bad but that cup/core separation in the water jug has me all screwed up about shooting them. I guess I'm just in the camp where we like our bullets to hold together and penetrate but dump energy between the 2 holes.
thanks,
Big Ed

A 7mm 120 grain Hornady SST? Are you certain it wasn't the 139 grain SST or -- more likely -- the 139 grain Interbond? Could you post photos of the recovered bullets if you have a chance?

The 7mm 120 is a VMax. Not that it wouldn't work for deer out of a mild 7mm, but I'd be surprised if it out-performed a 120 BT on any impact test.

I’ve seen a fair amount of NBTs and Accubonds shot into critters of various sizes over the past 25 years. I’d say on average, the NBT exits more frequently than the Accubond... given similar cal/weight/game/etc. I’ve seen one deer stop a NBT of any caliber, and one antelope stopped a 100 grainer outta the .25/06. Never seen an elk shot with one. But I’ve seen Accubonds ranging from 90gr .243 to 210 .338s dug out of deer. Admittedly, every Accubond we’ve personally shot at animals has exited, and done good work on the way out.

130 Accubond, at 2800-3000fps launch speeds, is a pretty good way to roll for most anything you’d ever need to shoot.... just ask those .270 shooting homos.

The 7mm 120 SST is from hornady’s Custom lite line. If I’m not mistaken mv is 2,600 fps as a reduced recoil load. I have a pic somewhere and will post it later. It is picture perfect in my opinion and penetrated 4 milk jugs.
Big Ed

OK, thanks. Did you shoot at a different range so that impact velocities would be the same or at least quite similar? The 120 grain Hornady is traveling nearly 300 fps slower than your .260/120 Nosler.

243 85 XBT at 3100 mv worked great here....

https://www.24hourcampfire.com/ubbt...5-x-bullet-and-wild-hog-pics#Post2818293

[img]http://https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/galleries/12939920/120-sst[/img]
[img]http://https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/galleries/12939920/120-sst[/img]
This is said 120 grain sst from a Tikka T3 compact after traveling thru 3 milk jugs and caught by the 4th. Pretty dang close to what I call picture perfect expansion w/o cup/core separation which personally gives me confidence if i pooch a shot and hit a shoulder knuckle or scapula. I so wish I was a cool kid and could actually post my pics straight to the post instead of a link. Someone please help a brother out.
Big Ed

I'm not an SST fan, gave up on them years ago. I found them to be very accurate, but terminal performance wasn't consistent. IMO, there are better choices, NBT's being one.

I agree with the NPT being a great bullet. I'm always pleased when a Partition proves to be the best shooting bullet in a certain gun as with the .240 mentioned earlier.

Traded for this one, got rid of the 42 oz HS factory stock, dropped it in a 26 oz Hunters Edge. The HS SPL has a 700 footprint. The lighter stock revolutionized the handling of this gun. Losing a full pound of ugly was a stroke.

The 6500 has been replaced by a VX-6 2-12x42.

DF

IMO, that velocity was better suited for that bullet. The 85 TSX may not open quite as quickly as the 80 gr. TTSX with it larger hollow point under the tip. I'd say you have a good combo there.

DF