Sierra's 308WIN 155gr Palmas

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chemo

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Hello, precision noob here.

How come is it that Hodgdon's data has the 155gr palmas COL at 2.775'' but every receipe feedback I get for palmas never goes under 2.800''?

Trying to start playing with seating depth and this right here is a small problem for me. I'd like to load on the lands but starting at 2.775'' I'm gonna fidgit around a whole lot of time


imputs?
 
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Seat them .020" off the lands and shoot them. Sierra's are very forgiving when it come to seating depth. On a side note I believe the Imperial Meeting in the UK was just shot using ammo loaded to 2.800" the scores were very high.
 
Hodgdon's data is likely an attempt to comply with SAAMI overall cartridge dimensions (a .308W is maximum 2.80", in order to feed from magazines). Other loading data (for some reason calling them "recipes" really rubs me the wrong way, though I have no idea why) is customized for a particular chamber, and is usually intended to be singly loaded - that's why you might see 2.815" COAL, or 2.850" COAL, etc given. But to be honest, those are overall lengths that work well in somebody's particular chamber; a much more useful dimension, to use when developing a load for your chamber, is where their bullet was relative to the beginning of the rifling - was it touching, was it jammed in .020", was it jumping .020", etc?

Back in the "old days" of ~10-15 years ago when the Sierra 155 was loaded in commercially manufactured "issue ammunition", usually to 2.800"- (which often meant 2.775"-2.785" typical), people found ways of making that ammo shoot very well. One approach was to make custom, unusually short-throated chambers - a very common chamber you'll see in US Palma rifles is the "Warner 95 Palma", which was made with an especially short throat in order to shoot the 2.775" long ammo loaded for the 1995 Palma Match in New Zealand.

Since 1995, people have come to slowly discover that the Sierra 155 is actually quite tolerant of bullet jump. You should probably try loading your ammo at an OAL that gives you at least .020" jump from the lands as Maynard suggests; chances are it will shoot very well for you, and you won't have the handling hassles of ammo that jams a bullet into the rifling.

So if you are set up to measure where your rifling is, start your load development .020" off the lands. Or, even simpler, just load to 2.800" COAL (or even 2.775") and begin; more likely than not, you'll start with very accurate ammo. Work your way up, prudently, to full pressure and velocity; it's usually the case that accuracy and velocity consistency improve as you approach max.

The default choice for this sort of ammo is Varget - an awful lot of 1000 yard matches have been won with Varget/Sierra-155. H4895 has also recently started to look particularly appealing. Other first-rate 1000 yard loads commonly use N140 and Reloder-15.
 
thanks for the help,
Now thats the problem rnbra-shooter, I don't have the tools to measure where my rifling starts, I could go with the trial and error method but that could take a long long time, lots of bullet pulling! But hey, this redding competition seater will serve its purpose

I'm using h4895 by the way, many people seem to like IMR 4895 which I don't have but since h4895 and imr 4895 are similar powders, I figured it would be worth a shot.

Also, I'm just entering the reloading for precision domain (I've reloaded for pistols and my m14 where consistency really doesn't matter) should I start with finding the proper powder charge or proper seating depth? (finding the right powder charge for one COAL then playing with the COAL with that powder charge)

or both? that'd be with the data for h4895 being 43 to 46gr for a 155gr bullet;
3 rounds of 43gr 2,775'' and 3 rounds of 43gr 2,800''
3 rounds of 43,5gr at 2,775'' and 3 rounds of 43,5gr at 2,800''
and so on...
 
I would suggest that three round groups won't give you valid results. The sample is too small.
Are you going to be single loading, or using the magazine? If the rounds must go through the magazine, that will give you an absolute maximum. Just check that this length does not result in a bullet jamming the leade.
There are improvised ways of determining the length at which a bullet is touching the leade. Take a case, and slit the neck lengthwise so that the bullet is held in place, but can still slide back into the neck if pushed. Gently chamber this dummy round, close the bolt. The bullet should be pushed into the neck, and should be contacting the rifling. You will have to remove the round without pulling the bullet back out. A rod from the muzzle might help. Measure the length, subtract the suggested .020" and start loading.
Something to consider - you don't really want the cartridge overall length as a reference - you want the base to bullet ogive at rifling contact length. But if you are loading with a bit of a jump, this won't matter.
 
What's the rifle you're loading for? Is it a factory chamber and barrel, or a custom one? What kind of brass are you using?

For a friend's target rifle, we are loading 45.5 grains of H4895 into a Winchester case, a CCI BR primer (or a Federal 210), with a Sierra 155 seated to 2.805" (that's the first length I tried, it worked well, I haven't bothered trying to tweak it).

There's a good chance that you won't have to fuss much with the bullet seating depth, so save that for later. For now, just load to 2.800" (make up a dummy first, and just make sure that it isn't touching the rifling - if no rifling marks show up on your bullet, you're fine. If it is into the rifling, which is highly unlikely, you can go to 2.775").

Start low and work up. Nothing wrong with starting with the published starting load. It helps (greatly!) if you have a chronograph, and if you can also take your loading gear to the range. Prepare your sized and primed brass ahead of time, but throw your powder and seat your bullets at the range, as you need them. That way you just load what you need, as you need them, there's no need to preemptively predict what you might need to shoot.

I'd fire one shot at the starting load, then work up in 0.5 grain increments until you get to the published max; you're looking to see if pressure signs start to show (sticky bolt lift, cratered primers, all the usual).

If you have a 30" barrel, you should be able to get 2950-3025 fps before pressures start to show. Not quite sure what to expect for a 24" or 26" factory barrel (perhaps 2800-2850?)

Once you establish a range of powder charges that are safe, I'd try using one that is 0.5 grains below the highest charge you had that didn't show pressure signs (when I was loading for my friend's rifle, we got up to 46.0 without pressure signs; I went with 45.5 so that in case he is out shooting on a hot day there's at least a small bit of margin before pressures problems might crop up).

Load up five or ten rounds of this trial charge, and fire a group at 100 (ideally, chrono'ing as you fire the group). You're looking for small, round, consistent groups, with uniform velocity spreads. I fyou don't have rifle/scope/shooter problems, you ought to be able to fairly easily get to be shooting 5-shot groups that are reliably under an inch.

One thing about Sierra 155s, their tips are quite nonuniform. Don;t worry, this doesn't particularly matter. You may well see differences in seating depth (measured to the bullet tip) that varies .010" or even .015" from one round to the next. DON'T FIDDLE WITH YOUR SEATER ON A ROUND-BY-ROUND BASIS in an attempt to "fix" this, it isn't a problem. Your seater's stem contacts the bullet not on its tip, but on a ring some ways down the nose - this location is much more consistent w.r.t. the bullet's cylindrical portion (which is what engages the rifling). Just set up your seater to give you "typical" COAL readings of 2.800", and don't worry about apparent +/- .010" variations in COAL.
 
Its a rem 700 chamber, 26'' barrel. I'm loading by hand
What kind of groups would you suggest to find proper powder charge tiriaq? 5? 6? 10??

I do not have a chrony and do not have (or can't justify yet) the money to invest in one.

So far I have only shot a box of winchester (the cheapest box) to sight in and I will use this fireformed brass to reload the 155grs. I'm thinking they will be sufficient for finding proper powder charge and seating depth but plan on upgrading to lapua as soon as I score a bag of 100
 
I would suggest a couple of five shot groups with each combination at the very least. This might be enough to show a pattern.
Suppose a rifle is capable of firing 10 shot groups no smaller than 10". Three consecutive shots could be touching. So could five. If you fire enough rounds, the actual 10" grouping capability will be revealed.
 
as I was going downstairs to play with the seating depth just made an interesting discovery.
I bought the bullets from Wholesale sports and the website says they are Palma, my cart said Palma and so did my bill. I just looked at the box and I know Palma's product number is 2156

What I actually have here is a box of 2155C, 155gr hollow point boat tail match kings, so just forget every mention of Palma (altough I doubt they really differ)
 
OK, factory Remington chambers tend to be quite long and sloppy. Load to 2.800" without any worries of hitting the rifling. In your load development you can try different seating depths if you want, but I would expect that you would see little if any change at all from varying your seating depth (this is because Remington factory chambers are so hugely long, that varying your seating depth from say 2.775" to 2.850" will simply vary your jump from 0.200" to 0.125", ie. any way you slice it it will still be "way lots" of jump).

When you're looking for pressure signs, you only need to a single shot or two at each charge weight.

H4895 in Winchester brass and Sierra 155s are a well-known quantity. Chances are, 45.0 or 45.5 or 46.0 grain will be safe and accurate in your rifle. Start low, work up there in half grain steps, verifying that these end up being safe in your rifle.

Once you have a safe load that is toward the upper end, you can load up a bunch (20 or 50) and do some testing/verification. Shooting a number of five round groups is probably a pretty good way to start testing your ammunition, and getting practice with your rifle.

Winchester brass is actually quite good. I use Lapua, and I also use Winchester. You'll likely find that the Winchester is quite light (about 156-ish grains without a primer), whereas the Lapua is a bit heavier (171-173 grains unprimed). Most other kinds of good commercial brass (Norma, Hornday, Remington etc) are in the 165-grain neighbourhood. You'll find that the Winchester brass has slightly greater internal volume (this is one of its advantages), any you may need 1/2 to 1/2 a grain more powder than you would in a 165-grain case. And the Lapua is slightly smaller, you might need to use 1/4 to 1/2 grain less.

The Sierra #2155 is the older "Palma bullet", it was introduced in 1992. (2155C means that its a box of 500, I think). Their new and improved design, the #2156, now gets the "Palma" label it seems.
 
Yeah I just gave up on trying to figure the chamber lenght, but you've just confirmed, "remington chambers tend to be quite long" hell yes mine is. Using tiriaq's technique I was seating to bullet so shallow that I doubt any pressure would've built behind the bullet.
 
Simple method. neck size a brass. Seat a bullet so it just goes into the neck (measure the OAL to the ogive). Put jiffy marker on the bullet circumferance. Chamber it. Extract and remeasure to the same ogive location. WHat was the change in OAL? There should also be 6 definite marks on the bullet from the rifling.

Now seat a bullet so the ogive is now a few thou shorter then this measurement. Jiffy, rechamber, any rifling marks? Keep reducing the seating depth until you only get 1 or 2 marks (there seems to be one or two leads that are always a bit longer).

This becomes your baseline ZERO. Adjust your ogive to be 10 or whatever thou shorter then this measure and you are good to go. You can always chamber a rd at this OAL and there should be no marks left on the bullet.

Takes a few try but it is simple and works.

Jerry
 
I tried that to no good, I could only see clear marks of rifling past 2,860'' and even if I back 0,020'', 2,840'' is still quite shallow for the 155gr

thanks for the help anyhow everyone, I'll just sit them around 2,800''

mysticplayer said:
Simple method. neck size a brass. Seat a bullet so it just goes into the neck (measure the OAL to the ogive). Put jiffy marker on the bullet circumferance. Chamber it. Extract and remeasure to the same ogive location. WHat was the change in OAL? There should also be 6 definite marks on the bullet from the rifling.

Now seat a bullet so the ogive is now a few thou shorter then this measurement. Jiffy, rechamber, any rifling marks? Keep reducing the seating depth until you only get 1 or 2 marks (there seems to be one or two leads that are always a bit longer).

This becomes your baseline ZERO. Adjust your ogive to be 10 or whatever thou shorter then this measure and you are good to go. You can always chamber a rd at this OAL and there should be no marks left on the bullet.

Takes a few try but it is simple and works.

Jerry
Click to expand...
 
You mean that the bullet is barely in the case at 2.84"?

The smallest amount I have had a 308 bullet into a case neck was approx 1/8". Worked fine but wouldn't be my choice for mag feeding :)

As long as the bullet fully engraves in the rifling BEFORE leaving the case neck, you have a chance of making it shoot. If the bullet has to jump unsupported, MOA would be about the best average.

You could always go to a heavier/longer bullet.
Jerry
 
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