Home Forums Hunting & Shooting Ask The Gunwriters Speer BT vs Sierra GK

Anyone have any experience on comparative terminal performance? My guess is that the GK is a little softer, but that's just a guess.

I have a 280 which likes 130gr Speer BTs and a 270 that likes 130 GKs. Actually the same load in both, and MVs are about the same.

Just wondering if the performance will be about the same when they collide with bambi.

I gotta follow this one.

My experience says the Speer BT is the softer of the two.

I've never shot them both in a similar caliber/weight/velocity window to see which is tougher, but I know that both will knock big holes in stuff when you are talking .277-.308cal and deer-sized game. Most of my Speer BT experience says they are pretty dang soft, even at 7mm-08 speeds, but this also makes them an effective killer.

I do happen to have on hand both the Speer and Sierra 130 gr. BTSP's in .277 and if my gallon milk jug collection gets up to 8 I can test them against each other. Do you have a particular velocity window you would like to see tested? My 7MM 130 gr. bullets are the Speer flat based Hotcor design.

MV in both cases is just under 3100. Thanks!!

rickt300, the Speer BT are not Hotcore bullets. They are two very different designs.

I know that, exactly why I mentioned that I didn't have any Speer 130 gr. 7MM BTSP's only the Hotcor flat based bullet. I do have some in the 145 grain weight but I think that bullet is too far from being a valid comparison.

Might be able to pull the test off tomorrow. My speeds are right at 3100 fps. Will test them at 100 yards from muzzle and hopefully capture what is left of the bullets. They are both pretty soft and water is a tough test.

I tried both in my 6mm and 260 and went with the GK's. They grouped more consistently. and I just like them better. I have gone to slowing them down down because most my shots now are close in. Have used them wonderfully at long range a bit faster but 3100 is too fast for them to me. . Lightly loaded they are a great bullet.

Lightly loaded, they are great, but heavy for caliber and they are even better. The speer are garbage for accuracy. Weigh some and let me know how many grains each bullet differs from the next one in the box. The game king is much more uniform and potential for accuracy is far greater. Terminal performance is just fine with a SGK, if you load them a little slower like you said or go heavy for caliber. With that being said, the speer bullets will work just fine on game like deer, if you can get them to fly straight.

I've been hunting with 130 Grain SGKs in my .270 Win. and 100 grain SGKs in my 6mm-.243s for 40 years and have lost very few animals due to bullet performance. I tried Speer 130s once and had some bullet failures with both my .270 Win. with the 130 grain and once in my 6mm Remington with 100 grain. Those two times made me a SGK fan for ever because the SGKs never let me down. Could have been my luck but you'll play hell getting me to change now.

I've had great luck with a couple other Speer bullets in other calibers but the SGK is my go to for my .270 and my .243-6mms.

Guys, the Speers can be just as accurate as the Sierras, but they will require a different seating depth and possibly different powder and charge to be so. If you are talking a 300 Savage, they are just about interchangeable.. A 270 or 300 Mag, not so, and definitely not with small 6.5's and 7 mm's.

Both are pretty soft, but very effective deer rounds below 3000 fps. Pretty messy at high speeds. Speers shoot a little flatter than the GK, but not enough to worry about.

Well the results are in, Muzzle velocities for both bullets right at 3100fps. The both shoot tight groups in my Ruger 77. I shot the Speer 130 gr. BTSP first and all that was in the fourth gallon jug was a core base weighing 32.2 grains. No jacket material though a shard of it was sticking out of the third jug. The Sierra bullet still had 77.3 grains of bullet in the fourth jug to include a nicely expanded jacket, the core base and some lead fragments about the size of #6 shot. It also put a dent in the far side of the last jug where the Speer bullet left that untouched. The jugs were in front of my 100 yard backstop and shot at that distance. The Sierra bullet actually split the first three jugs (destroyed the first and second) where the Speer bullet absolutely destroyed the first two and it looked like the core base just penetrated the third jug and ended up in the fourth. I found one tiny fragment in the third jug and the jacket fragment sticking out of the back of that jug. This would suggest the Speer bullet might open up farther out than the Sierra.

Speer boat tails are deliberately made soft.

Yes and put in the ribs of just about anything seem to cause a quick demise!

Yep, so they can be formed easily. The lead alloy used in the Hot-Cors is harder.

The lead alloy used in Sierra GKs is about average for cup-and-cores.

Thank you rickt300. That answers the question very well. Guess I’ll have to be a little selective in how I stick these Speer BTs in Bambi. I appreciate your efforts.

An underappreciated option. Good choice for distance and low impact velocity.

Last years ME whitetail (205# dressed) got a 270 gr BT at about 100 yds. Through onside shoulder blade, rib, vitals, rib, finished by wrecking the off-side shoulder ball. No exit. Maybe 10 yd run. Hobble, I meant. Impact velocity would have been about 2500 fps. No complaint......from me.

Not the exact bullet in question, but it illustrates the point. I shot a deer with the Speer .270 150 gr. BT at about 20 yards. MV was 2850. Hit a rib going in, and there were four exit wounds. 1 small piece of jacket was recovered under the far side skin. It was about a 110 pound whitetail doe. Since most of my shots Are short, I don’t use that bullet anymore. The Sierra GK I’ve used were somewhat tougher.

Old70