30 cal 155gr Matchking Palma Bullets

[JonM]

I want to try the 155gr Matchking Palma bullets for my 308 700 Varmit. It seems like the high .504 BC with the low weight should be awsome. Anybody have any experiene with these yet? A friend of mine is using them for his 30-06 and says he is having problems with runout at the overall length he wants to run. He is running them .045" off the lands to seat them far enough in the case to reduce runout. Does the OAL even matter that much? I load two different lengths, one for my 700 and one for my buddies LR308. I shot some of the shorter loads in my gun and couldn't see a difference. Any info is appreciated.

Thanks,
Jon

[firewrench044]

I use them in 308 and 3006
In all my rifles they work best 10 to 15 thou. off the lands
but are less sensetive than the other brands of 155s to a larger jump
to the lands
pn 2156C are much better than the older Sierra 155s
Very consistant in weight and all dimentions

( used in 2-M1 Garands, a M1D Garand, 1903 Sping., 1903A3, 1903A4,
an Israeli Mauser and 2-Indian Enfields )

[Bart B.]

Note that Palma teams around the world chamber their barrels such that the load used in world championships will push Sierra's bullets into the lands a bit. Best accuracy's attained this way according to those who shoot good enough to get on the teams. This is one reason why samples from the ammo lot to be used are sent to them months ahead of time so chamber reamers can be made for that ammo.

Back in 1991 when a few of us worked up loads for Sierra's then new 155-grain Palma bullet, we all seated them about .010" longer than leade contact. The load load selected (45.3 gr. of IMR4895, new Winchester case, Fed. 210M primer) used later that year by several Palma team members from around the world in a big match shot about 1/2 MOA or better at 600 yards in their rifles; note a variety of chamber and bore dimensions were used in those barrels. A picture of a production test group in a fall 1991 issue of Handloader Magazine showed a 20-shot 2.7" group at 600 yards.

A few key elements of the 29 to 31 inch barrels used to shoot them. 1:12 to 1:14 twist barrels shot them the most accurate. 4 groove barrels shoot them better than 6 groove barrels. Groove diameters need to be at least .0005" smaller than the bullet (which was .3084") and some barrels were as tight as .3065" for groove diameters. Bore diameters anywhere from .3000" down to .2980" worked well. The 30" Obermeyer barrel I used to help develop the load and allow me to shoot the high 4-day aggregate score in the match had .3070" groove and .2980" bore with a 1:12.7 inch twist.

[old roper]

This is from Obermeyer site on his Palma barrels


What was the original purpose of having a tight groove diameter, and how have circumstances
changed?

The idea has long persisted that a tight groove diameter works better, particularly in a Palma rifle.
In part, this perception resulted from the past use of under-size bullets in certain Commonwealth
countries. However, all currently-manufactured Palma bullets I have checked are now .3080" or
larger, and I no longer make tight-groove .3065" barrels. I now make Palma barrels with a minimum
diameter no smaller than .3075".


http://obermeyerbarrels.com/faq.html


Here is interesting article

http://riflemansjournal.blogspot.com...d-barrels.html

[Bart B.]

Old roper, I well know all that stuff you mentioned above. Even talked with Boots Obermeyer years ago about it. The Brits and their Commonwealth countries were the first ones to use .3065" groove diameter barrels as their arsenal bullets mic'd .3075" or thereabouts. They had to shoot arsenal FMJBT 147-gr. bullets, but good lots of it shot very accurate. That all started in the late 1960's (?) when the Brits switched from the .303 round to the 7.62 NATO ammo.

And I had many a talk with Bob Jensen who loaded the 1991 Palma ammo on two Dillon 1050 progresives about those "fat" Sierra match bullets and the barrel specs that would shoot them. Sierra's HPMK's were typically .3082" and a bunch of us were surprised to mic those prototype and later 155's at .3084". But they shot very well in some of those Commonwealth .3065" to .3070" grove diameter barrels.

I've shot Lapua's FMJRB 185-gr. match bullets mic'd at .3092" in Hart bolt gun and Springfield Arsenal M1 barrels with .3078" groove diameters from .308 Win. cases. Easily went into 1/2 to 5/8 MOA at 600 yards.

[old roper]

Bart B, I fully understand about the use of tight bore barrels and reason I post those article just let everyone understand why they were used in Palma matches.

[Bart B.]

Old roper, posting that info for all's a good idea. I'm a firm believer that the more facts we know the better off we may be to make decisions.

Note virtually all the best scores in competition have all been shot with groove diameters smaller than bullet diameters. Too bad most factory rifle's groove diameters are larger than the bullets they shoot.

Winchester's groove diameters have been on the big size for years. But Winchester was smart enough to have both their match bullets and those of Western Cartridge Company be in the .3087" to .3088" range so the factory match rifle barrels with .3082" to .3086" groove diameters would shoot them very accurately. Remington's factory barrels are tighter and that's why I think they've typically shot more accurate than Winchesters.

And both Lake City and Frankfort arsenals were smart enough to make their 30 caliber 172-gr. match bulets about .3086" in diameter so they would shoot pretty accurate in both M1 and M14 barrels whose groove diameters were not much smaller in their NM versions. Regular service bullets were around .3076" to .3081".

[brokenanew]

Im glad this was posted. Was looking at trying the Palma bullets. What exactly makes a bullet a Palma? Im ignorant to this. Whats the difference and are they senstive to seating depth...as he asked?

[Jimro]

Yes, but in everything there is an exception. Generally the 155s don't like a lot of "jump" into the lands, but you won't know until you try them in your rifle.

Jimro

[Bart B.]

brokenanew, in 1991 when Sierra came out with their 155-grain match bullet for 30 caliber bores, it was such a success in its first match where it was the only bullet allowed later that year, the International Palma Committee (group of international rifle team reps organizing long ranges matches for .308 Win. chambered rifles) declared it the "Palma" bullet and was the only one to be used in International Competition.

A "Palma" rifle is chambered for the .308 Win. and uses bullets from about 147 to 155 grains. Standard arsenal 7.62 NATO ammo's used by most countries other than the USA. Rifles uses metallic aperture front and rear sights, 6.5 kilogram weight limit, 3.5 pound trigger pull limit, usually a 30-inch barrel and is the standard for this type of competition. 'Twas the British idea decades ago that to level the playing field in rifle competition, everyone had to use the same ammo but any rifle that met the rules could be used. That's still the rule today for international competition and in most regular matches in other countries. In the USA, handloads can be used for regular Palma matches unless issued ammo has to be used. In some matches, the bullet has to be 155 grains. In others, any bullet can be used.

Here's what a modern Palma rifle looks like:

[Jimro]

Bart B.

When did the US restrict the bullet weight to 155 grains? Last I checked German Salazar was still shooting 175's and 190's in US competition. I thought that the 155's was a requirement only for competing Internationally.

Jimro

[Bamashooter]

I load and shoot them in my sporterized remington made 1903 and it has always shot them under MOA. Great target bullet. I hunt with the 150gr gameking loaded the same as the palma so my POI stays the same.

[rox]

Does the OAL even matter that much?

They are pretty length tolerant - especially compared to VLD's, Lapua Scenar and such; you certainly don't need to stuff them into the lands to get great performance out of them. I know members of our (winning) Palma team who shoot them with jumps from 40 right up to 100 thou. I mostly shoot the 'old' Sierra (2155) and anywhere from 15 to 25 thou. jump allows close to a quarter minute performance at 300 meters and half a minute at 1000 yards. The high quality factory ammo we are issued for most Palma competition here also uses the 2155, and the results have been superb for the last few years; being factory ammo, the jumps are pretty large in most rifles.

..

[Bart B.]

Jimro, I should have stated that in some Palma matches shot in the USA, the 155's have to be used. In others, any bullet weight can be used. Thanks for bringing this to my attention. The NRA's rules for Palma rifles and ammo has changed several times since the late 1980's when I wrote the first rule for them that the NRA High Power Rule Book originally had.

Rox, having been on the US Palma Team (and other International long range teams) and one of the folks helping develop the load in early 1991 for Sierra's first 155, we've always shot them loaded such that they set back a few thousandths when chambered. This helps align them with the bore when they're fired. In the first match later that year when they were used in ammo provided to competitors, rifles with jump to lands of more than a few thousandths didn't shoot them very accurate. I've never been able to get any Sierra 30 caliber match bullet to shoot super accurate unless it's set back by the leade when chambered.

Brokenanew, jump to the lands amounts can also be affected by the angle the rifling has to the bullet. Note also that the more a bullet jumps to the lands, the faster it's moving when it goes into them. Higher impact speeds tend to deform bullets more than slower ones. All this aside, shoot at least 20 shots per test group then use whatever makes their largest ones the smallest. The accuracy one can count on all the time from a given load is the largest group it shoots. The smallest groups fired happen the least amount of times.

[Jimro]

Bart B.

Thanks for the clarification on the rules, odds are they'll be different again next year. The real reason I don't shoot Palma is that it is even more expensive to get into than Service Rifle. Maybe one of these days I'll find a Savage Palma rifle in a used rack somewhere and only have to acquire a decent set of sights for it (Stranger things have happened in the gun world).

Jimro