HPBT vs Palma contour bullets

[TheBelly]

What are the functional differences between a HPBT (Sierra Match King: http://www.midwayusa.com/product/1482173051/sierra-matchking-bullets-30-caliber-308-diameter-155-grain-hollow-point-boat-tail ) and a Palma contour bullet: (Barnes Match Burner: http://www.midwayusa.com/product/136841/barnes-match-burner-bullets-30-caliber-308-diameter-155-grain-boat-tail-palma-box-of-100 )

[Delfuego]

Here is some info on the Sierra Palma bullets. They have a little different shape and higher BC than the standard SMK 155gr. I believe they may be a little more fickle to load as well.

"Sierra created the 30 caliber 155 grain HPBT Palma to fill the long-range demands of the Palma and other long range shooters. The #2156 Palma bullet has a longer, more streamlined 9 caliber ogive, slightly longer OAL and a pointed meplat, which is a first for Sierra Bullets."

Check out these...
https://www.sierrabullets.com/store/product.cfm/sn/2156/308-dia-155-gr-HPBT-PALMA-MatchKing
http://www.midwayusa.com/product/1482176707/sierra-matchking-bullets-30-caliber-308-diameter-155-grain-palma-hollow-point-boat-tail (http://www.midwayusa.com/product/1482176707/sierra-matchking-bullets-30-caliber-308-diameter-155-grain-palma-hollow-point-boat-tail)

Hopefully someone a little more experienced at reloading or BR / Palma shooting can chime in with more knowledge.

[Hoser]

Palma isnt a contour. It is an International type of competition that requires use of the 308 Winchester, iron sights and a max bullet weight of 155.5 gns. That way all competitors are on an equal playing field.

The older 155 does not have a really slippery contour like the new one. That comes at a price. The new contour is not as forgiving as the old when it comes to seating depth.

If you find out that one that works well in your rifle, buy as many as you cant afford. Thats why I have many thousands of the Lapua 155 and Sierra 2156 on hand.

[TheBelly]

Palma isnt a contour.

Understand this.

Do I dare start a new thread to ask about max COAL for the 155 SMK? I've loaded a few rounds with a COAL of 2.8" because my pmags have a 2.810" available space, and the 155s didn't push in very far. I'm guessing I have the bullet loaded maybe 1/4 - 1/3 of the way up the ogive from the boat tail portion.

My concern is two fold:

1) is that enough seating depth to keep the bullet in the case?

2) two manuals I have say to load (155 SMK) to a COAL of 2.775". My fear is that I'm going to compress the powder if I do that, as the case is pretty full of varget as it is (45gr). How do I tell if I'm compressing the powder? (if the answer is so simple as "if you can hear the powder shaking in the case, then it's not compressed" I'll allow you to laugh at me and call me a dumbass... but to my face this time.)

[stubbicatt]

TheBelly, in answer to your question 1: I guess load a couple of dummy rounds, measure the OAL and case head to ogive length, and gage them with a runout gage, a couple of times to get really good solid data, and cycle them through your rifle maybe 6 times, and between each "cycle" measure again. If the cartridge stands up to repeated cycling then you will know. If concentricity is effected or lengths change, then you may wish to seat a bit deeper.

In answer to your question 2: The quick and dirty way to determine if you are compressing loads is to drop the tail of your micrometer into the case to determine the level of your powder from the case mouth, and then measure your bullet from the base to the same measurement, and either scribe a line or other reference on the bullet with a sharpie and seat the bullet. If the reference mark is above the case mouth you are not compressing. Another way I can tell is that seating force gets really stout as the load is compressed, and often the bullet won't seat to the depth I want.

There may be other methods. YMMV. :)

While I respect your desire to eke out the best performance from your handloads, it seems that your velocity goals may be better met by a cartridge other than the 308? That's a stout load of powder.

[Tim K]

What's wrong with compressing the powder? I have a number of crunchy loads. BTW, you'll hear a compressed old when seating the bullet.

I couldn't quite tell from your description. Is the start of the boat tail seated deeper than the bottom of he neck, the start of the shoulder?

[TheBelly]

That's a stout load of powder.

My loading manual (and folks that have much more experience than me) say that it's a good starting load for my Larue rifle. I can always go either way with it. Maybe I'll do a ladder test to get UP TO the 45 gr.

[TheBelly]

What's wrong with compressing the powder? I have a number of crunchy loads. BTW, you'll hear a compressed old when seating the bullet.

I couldn't quite tell from your description. Is the start of the boat tail seated deeper than the bottom of he neck, the start of the shoulder?

My understanding is pretty limited, but I thought that compressing the powder can increase the overall pressures in loaded ammunition. I'm afraid of wrecking a good rifle by being un-cautious from the get-go. I'll ask 8000 questions before I pull a single trigger. I'm in no hurry.

I haven't measured, but I don't think the boat tail portion is even extending past the neck. I'll measure more when I get home. Like I said, I'm in no hurry and I refuse to rush to failure.

[TheBelly]

If you find out that one that works well in your rifle, buy as many as you cant afford. Thats why I have many thousands of the Lapua 155 and Sierra 2156 on hand.

Oh as soon as I find something that my rifle likes, I'll be burning up the old debit card.

[jerrymrc]

My understanding is pretty limited, but I thought that compressing the powder can increase the overall pressures in loaded ammunition. I'm afraid of wrecking a good rifle by being un-cautious from the get-go. I'll ask 8000 questions before I pull a single trigger. I'm in no hurry.

I haven't measured, but I don't think the boat tail portion is even extending past the neck. I'll measure more when I get home. Like I said, I'm in no hurry and I refuse to rush to failure.

Basic rule of thumb is stick powder is ok to compress and ball is a no-no. At least that is what I was taught many moons ago.

[TheBelly]

While I respect your desire to eke out the best performance from your handloads, it seems that your velocity goals may be better met by a cartridge other than the 308?

I agree that there are 'better' cartridges and calibers for long long long range, such performance doesn't come at a cost.

When it comes down to barrel life, availability of components/loaded ammunition, and a multitude of proven performing recipes (for a novice reloader like me)... well, I'd like to stick to the .308.