Sierra 155 gr.HPBT bullets

[cw308]

Using a Rem 700 LTR 308 Cal. 20" brl. 1-12 twist, groups well with 168 gr.HPBT. Rifle range is 200 yards max. Has anyone out there reloaded the 155, I know it's used for PALMA matches with 30" brls. at long ranges, I was thinking with a slightly lighter bullet at a short range of 200 yards it might group even tighter.What do you think. Chris

[Jim Watson]

I think it might or it might not group tighter.
There is no way to know except to buy some and shoot YOUR LOAD in YOUR RIFLE.

[Jimro]

The 155s should be just fine, but it is a crap shoot whether YOUR rifle will prefer one load or another.

Jimro

[dahermit]

The 155 grain PALMA target bullets are marked "PALMA" on the box. If that is what you have, not some other Sierra 155 bullets (Game Kings), they are very accurate when you work up the correct load. As with any bullet, you have to find the powder and charge weight they like.

[Art Eatman]

I admit to not having kept current, but the GameKing HPBT used to be 165-grain. Has that changed?

[sc928porsche]

sorry, read wrong

[emcon5]

Sierra makes .308" Gamekings in 150, 165, 180 and 200 grains.

[Bart B.]

I doubt the 155's would shoot any more accurate than another Sierra match bullet from 135 to 190 grains in your barrel. But with its 20 inch length, accuracy beyond 600 yards will be iffy, at best. That barrel's not long enough to get enough muzzle velocity to keep them supersonic in cold weather past 600 yards. In warm weather, they may be OK to about 700, but I wouldn't bet on it.

With factory barrels, Sierra's hunting bullets shoot darned near as accurate as their match bullets. Few of us will be able to tell the differnce. Oft times, their flat based hunting bullets shoot more accurate than any boattail bullet in factory barrels. In the 1950's before Sierra made their FMJBT 180 and 200 grain 30 caliber match bullets, top competitors used their spitzer boattail versions in those weights in the finest match grade barrels available. Scores didn't go up a whole lot with Sierra's match bullets when they were finally available. Even after these two bullets came out, many folks used Sierra's 150 and 165 grain spitzer boattails at 200 and 300 yards as they shot almost as accurate as the 180's and even the 168 HPMK"s when it came out.

[tobnpr]

2600 fps with the 168 SMK out of a 20" barrel is easily accomplished. 2700 isn't unheard of.

JBM shows that bullet at 0 degrees centigrade, sea level, 29.92 in Hg, as still supersonic (1148 fps) at 900 yards.

It's still 1196 at 800 yards at zero degrees Fahrenheit.

Not much less (1158) at 20 below zero.

No temp on this planet that'll keep a 168 SMK from being supersonic from a 20" barrel past 600 yards.

[Bart B.]

tobnbr, having chrohographed M852 ammo with 168's from a few M14's, none of them went over 2560 fps at 15 feet from their 22 inch barrels. But the same ammo's shot just over 2600 fps from 24 inch Garand barrels. I've never seen a Remington factory barrel with as tight of bore and groove diameters as those M14 or M1 barrels had, so their velocities will even be lower. And velocity's gonna drop about 25 fps per inch going from 22 back to 20.

Would be interesting to see what the peak pressures are for any 20 inch barrel getting 2600 fps at the muzzle with Sierra 168's out of a .308 Win. case. Especially with any powder that'll shoot 'em accurate. But I agree that 2600 fps with the 168 SMK out of a 20" barrel is easily accomplished and 2700 isn't unheard of. Lots of folks load ammo way, way over maximum safe pressures.

[Jimro]

Bart B,

There are some powders on the market now that allow those muzzle velocities. Alliant says 2,725 from a 24" barrel with Power Pro 2000-MR and 2,782 using AR Comp. Assuming 25fps per inch then that would be about 2,625 or 2,682 from a 20" barrel (would really need to confirm over a chronograph).

Hogdon lists 2,828 fps with CFE 223, and assuming that we lose 150 fps from a 26" barrel (my assumption as to how that velocity is so high) to a 20" barrel that is still a respectable 2,678 fps.

Still, those are max charge loads and not a significant performance increase over a standard service load of M852.

Jimro

[HiBC]

Sierra,in the last couple years,came out with a new 155 gr Palma.It is now called the Palma.It has a BC of around .500.For me,in the AR,loaded mag length,accuracy was mediocre.That is no reflection on the bullet.It may shoot very well in your bolt rifle with over all length tuning.

The 155 gr bullet that was the Palma bullet ,previous generation,has less of a BC.IIRC,its about a .450.(advertised).Now it is called the 155 Matchking.

That bullet shoots very well from the two AR's I tried it in.

In comparing velocities between gas and bolt guns,the gas port costs velocity.All other things equal,you may approach 100 fps more velocity in a bolt gun.

[geetarman]

I have tried 155 +/- bullets from various manufacturers as well as loaded ammunition from various makers.

It just will not group in my 700P.

It just does not matter about the powder or the load, my gun won't shoot it well.

Step up to 165-175 grain bullets and you can do no wrong.

I have found out the hard way not to use them in my bolt gun.

[Bart B.]

Jimro, I know there's powders out there that shoot bullets out extra fast and I didn't think of that. Most of 'em are ball powders. I don't know of any ball powder that shoots match bullets more accurate than extruded powder. And I don't think any powder slower than Varget should be used with 155's or 168's if best accuracy's the objective; their pressure curves are typically not all that consistant and repeatable.

HiBC, it's been my experience (and that of many others) that Sierra's 155's will shoot very accurate out of any barrel whose groove diameter is at least .0004" smaller than their .3084" diameter (at least all the one's are that I've measured) and have uniform dimensions for diameters and twist. Of course the barrel must be properly chambered and fit to a decent receiver that's properly affixed to the stock, too. I don't think a difference in BC has anything to do with accuracy. While a gas port costs velocity, the difference between a ported and unported barrel is insignificant. And it has nothing to do with accuracy. There's a greater spread in velocity across several people shooting the same rifle-ammo combination than between a ported and unported barrel both with the exact chamber, bore and groove dimensions shot by one person. And if Sierra's match bullets won't shoot as well as their owner expects, it's not the bullet's fault.

[4runnerman]

Im with geetarman here. I have used both 155's and 155 palma's. Did load development and all. After all was said and done i said the heck with it all and went back to my 175's. The 155's did ok,but the 175's did better and i like the fact im shooting a heavier bullet.

[Jimro]

Bart B.

If you don't want to use the ball powders, Reloader 17 is an extruded powder that offers the same velocity boost over traditional loads.

Although the "traditional wisdom" about ball powders not being as accurate is something that I'm questioning more and more. I've been using Power Pro 2000-MR and easily exceeding the accuracy specs for Mk262 ammunition. I guess if I were a benchrester I might care a lot more. From a practical standpoint I don't know of any service rifle shooter good enough to separate his/her groups by which were shot with ball or stick powder.

Jimro

[Bart B.]

Jimro sez:

From a practical standpoint I don't know of any service rifle shooter good enough to separate his/her groups by which were shot with ball or stick powder.

After the adoption of the M852 match cartridge in 1981, the last lots of M118 Match were loaded in 1982. After 1982, the M118 was referred to as M118 Special Ball denoting that it was no longer intended for match use, but rather for use by snipers. Some lots loaded in 1982 and 1983 were still loaded with a nominal charge of 42 grains of IMR 4895. In 1984 the powder type was changed to WC846, the regular ball powder used to load M80 ball, all lots loaded after this date use WC846. Shooters forced to use this ammunition were very disappointed in the special ball characteristics and felt that the accuracy of all lots of this ammunition left something to be desired. The not-so-accurate M118 match ammo was first noticed in the mid to late 1970's when curious shooters who had poor accuracy with some lots pulled bullets from the cases to check powder charge weight spread and wa la. . .ball powder inside!!!!

I'm one of them, so now you know of one. Lots of top NRA classified service rifle shooters noticed this in the early 1980's. I've had discussions with several folks from military teams in that era who all had tried various loads with ball powder before Lake City stuffed it in their M118 rounds; none got the accuracy that extruded powder produced. Some of those team members were snipers who had to zero their Rem. 700's with that stuff and also said any lot of M118 match ammo with IMR4895 was more accurate than M118 Special Ball. Even the US Palma Team developing loads in 1991 for Sierra's then new 155 grain Palma bullet tried several ball powders; horrible accuracy compared to extruded powders at long range.

Some military teams pulled the 148 grain bullets from M80 ball ammo loaded by Remington that had IMR4475 extruded powder then replaced it with a Sierra 168. Excellent accuracy through 600 yards was attained; better than any M118 match ammo. Replacing that bullet with 168's in cases loaded by Winchester with WC846 ball powder shot only a tiny bit better than the standard M80 ball ammo. I among many others have experienced this situation.

All that aside, there are folks who won't be able to tell the difference.

[Jimro]

Bart B.

WC846 had a hard time being lit properly by the #43 primer, there was an investigation (because delayed ignition would be a problem for the M134 minigun using M80 ball). Once the arsenal primer was upgraded to ensure no delays after 1986 I haven't heard of any gripes with accuracy until the change from WC750 powder to Reloader15 for M118LR.

It should be noted that the accuracy standards for match ammo were met using ball powder, which is from a rest. From a rest things like "ignition delay" don't show up on the target as readily as from a shooter trying to hold onto a target. So blaming the lack of accuracy solely on the propellent is a very "intuitive" answer, but it isn't the whole story.

Jimro

[Bamashooter]

I load the Palma Matchking 155gr bullet for my 1903springfield. I dont have my log in front of me but I think its 49 or 50gr of IMR-4895. It shoots sub-moa easily so I havent tried any other combinations with the powder. The Springfield is sporterized and scoped but its a darn good shooting Remington made 1903. It also shoots Remington Cor-Lokt 150gr ammo very well to. Those are the only two bullets Ive ever shot out of it.

[HiBC]

Bart B,

I want to clearly state I have no doubt the Sierra Palma will deliver world class accuracy and I think very highly of Sierra bullets.IMO,there was nothing wrong with the Palma bullet.Its just ,in my application,it did not get what it needed to perform.The problem was the application,not the bullet.

You may have a different experience,butIMO for some reason,maybe the shorter cylindrical portion of the bullet body,High bc generally translates to longer ogive and boat tail...it CAN be more finikky to get them to shoot.Sometimes a less VLD shape is more forgiving in something like an AR factory rifle.

On the velocity loss to the gas port,I have had a chrono for several years and general observation,I have noticed my bolt guns deliver close to load book velocities and my gas guns come up 50 to 100 fps short.

No big deal,I do not want to play whiz contest,we can disagree with a smile.

[Bart B.]

Jimro, M118 match ammo specs are mean radius averaging 3.5 inches at 600 yards. Extreme spreads of that will be in the 11 inch range. None of the ball powder charged M118 ammo shot in the 7 inch extreme spread range like the better lots of extruded powder lots. And the National Match lots in the 1960's shot extremes in the 6 inch range; mean radiuses of 1.7X inches. I've broken down several lots of M118 to check the powder used and all the not-too-good lots all had ball powder.

One doesn't have to be a crack shot to tell the difference between 1.8 MOA ammo and 1.2 MOA ammo. That's the typical difference in M118 ammo with the ball and extruded powders.

[Bart B.]

HiBC, when one makes comparisons between ported and nonported barrels' muzzle velocity, they better both have the same bore and groove diameters. Same firing pin impact force on the primers, too. And the same lot of ammo's got to be used. There's easily a 50 fps spread in muzzle velocity with the same load across several rifles of the same make, model, caliber and barrel due to tolerances in their bore and groove diameters.

[Jimro]

Bart B.

I'm not saying that ball powder with the #43 primer was as good as IMR 4895, what I'm saying is that there is a known delay in ignition issues with WC846 with military primers. http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA341390 The recommendation was to standardize to WC846FS (Flash Suppressed) as it showed more consistent ignition with either the #43 or #34 primers. The report states that case fill was critical in getting proper ignition with WC846.

Jimro

[30Cal]

I shoot the 125gr Speer TNT up close. Very accurate, low recoil and fairly cheap.

[cw308]

Thank you for all your info. Had to put my Dog down yesterday, my best friend for 14 years & I'm heart broken. It's a tuff thing to do. I didn't think I was such a softy, I will miss her.