Bullet jump to the lands.

[kilotanker22]

So My Winchester XPR in 300 win mag is a real nice rifle for the money. Problem I seem to be having is that none of my handloads seem to shoot as well as Factory ammunition.

I have good ES and SD numbers. And have seated bullets from .030-.075 off of the lands. The Factory ammo I have is .130 off of the lands.

I am wondering If Maybe I just need to work on my seating depth a little more and go further out.

For example.
Remington 180 corelokt factory ammo is .130 off the lands.

What if I seated the 180 Sierra's and the 200 eldx out that far? Have you guys ever seated bullets. So far away from the lands with good results?

Just scratching my head a little. I have never loaded so far out. And the loads I am shooting should be better than they are grouping. Factory ammo hovers .5-1 MOA
Handloads are averaging 1.5-2.5 MOA.

I don't think it is inconsistent technique, because I have no trouble with any of my other rifles. It is also not recoil induced.

[kilotanker22]

Also I think with mentioning is that so far my best grouping loads were .075 off the lands.

[LineStretcher]

There's many schools of thought about this. It's well known that some manufacturers have longer free bore than others and some even slightly swag the bullet in the free bore. What that means is that some will take kindly to less jump and some won't.

I have a couple of rifles that prefer the jump and others that don't. My Weatherby Mark V .308 likes to sit back around 100 while my Bergara 6.5C likes to be right up on the lands at .020 off.

My Weatherby Vanguard S2 .308 was sweetened on the Remington Core Lokt ammo and it grouped amazingly well. I decided to mirror them with my reloads and then adjust in small increments. Like you, I did not see any improvement and the closer I got the worse my groups got.

The COAL of the .308 is 2.80 but the Nosler book say's 2.75 for the ABLR's. I set 5 to 2.80 and 5 to 2.75 and the 2.75 shot tighter groups.

So, it all depends on your rifle and the old saying that no two rifles are the same still has a lot of merit.

[kilotanker22]

Well this particular rifle has a pretty long throat to begin with. With the 200 grain ELDX COAL is 3.525. with the 180 Sierra SBT it is 3.490.

Maglength used to be way shorter until I modified the mag so I could get closer to the lands and still use the mag.

If I load the 200 grain ELDX to max COAL. I would be .185 off the lands.

I am gonna load some up tonight that are .120 off the lands and see how that goes.

[Dufus]

Just for thought: the most accurate rifle that I have shoots 3/8" C to C 10 shots at 100 yds. I don't get the barrel hot....ever.

That load is seated 0.204" off the lands.

[std7mag]

Kilo,
Either your decimal poilt is off, or your thinking backwards.
0.130" off the lands is seated further IN than your stated 0.030-0.075".

Out of my Savages, and Rugers, most cup & core bullets like seated 0.020" off the lands. ELDX and ABLR included.
VLD being the exception at 0.005" off the lands.

With the throat being so long, my 284 Win has shot well at the loaded length shown in Hornady's manual.

[kilotanker22]

Yeah I guess I mis spoke. I was referring to seating them deeper. And when I said Farther out, I should have said further away. Since I was talking about distance from the lands

[kilotanker22]

Every rifle I have ever loaded for. I have found a sweet spot between .020 and .050.

I loaded so e last night that are seated deeper. I will be testing them today hopefully.

[kilotanker22]

I also switched powder. RL 26 gives me impressive velocity, but I guess maybe this rifle just doesn't like it. I loaded a test with RL 26, then a couple test loads with RL 25 for both the 200 and 180 grain slugs. I also plan to try some of that IMR 4451 End. It's faster for sure, but should be able to get some decent spreads with that powder.

[RC20]

This is not an unknown aspect. My 7mm Rem Mag shot factory as good as any handload I ever came up with.

So yes you can work with COAL both closer and further out and see.

I have a Savage 308 with an aftermarket barrel. 308 is supposed to be the easiest in the world to get good loads. Failed miserably (3/4 was the best it would do)

I got some Hornady ELD in 168 and suddenly I have a tack driver (3/8 MOA)

Others report the same, picky rifle and one day the right bullet and its good

But its only one bullet for that gun. Pick another 4 or 5 and maybe one will work.

What I will also do is if I get a decent load going, I will duplicated that SPEED with another powder (using the same book to cross it over, no so much the speed they got as a match up for whatever mine does - velocity not the same as Hornady got say, but it will be the same for my gun whatever it is 100 fps above or below)

Upshot is that a good 4350 load did even better more consistently better with 4831.

Power seems to have some affect but hitting the right velocity with the right bullet more so (then you can fine tune)

My 30-06 will shoot a lot of stuff well. The 308 and the 7.5 Swiss Savage build (with a very5 good mfg barrel) are picky. go figure.

Your worst situation is one that likes a really expensive bullet like Berger (the 7.5) argh. I found an option that is looking good.

[F. Guffey]

I am the fan of the running start, I want my bullets to hit the lands 'a-running' I want my bullets to have 'that jump'. As opposed to what? I do not want my bullet setting at the lands wondering if it is going to get past the rifling before the pressure gets serious.

F. Guffey

[std7mag]

As RC20 says. Right bullet, right speed.

You may want to try playing with different bullets.
I had bought some Accubonds, really wanting them to group well. Didn't matter what i did, it just wouldn't come in.

Forget RL25. Great velocities, dismal accuracy.
I quit buying it.
Lazzeroni also recommends against using it reloading their cartridges. And if anyone likes speed, it's Lazzeroni.

As for IMR4451, it groups fairly well. But the velocity just isn't there.
I quit buying it also.

[Unclenick]

Kilotanker22,

Read this article by Berger. It shows the long ogive bullets prefer as much as 0.0150" off the lands. I have a couple of theories about why this works, but no solid proof of the cause.

There used to be an older page online describing how a Somchem customer (back when they still had their load development service), a customer brought in an old 8 mm Mauser his grandfather had used. It had a very worn throat, but he wanted to hunt with it for sentimental reasons, so Somchem agreed to try to find something it would shoot. After establishing a baseline load, the deeper they seated their bullet, the tighter the groups got until, in the end, it shot tighter groups than any other sporting rifle they'd ever tuned a load for. Something like 0.27" at 100, IIRC.

I think the thing in common with a magnum rifle is the old Mauser's "shot out" throat had moved forward, giving it some of the characteristics of a long freebore gun. Why those seem to prefer a long jump is probably a clue in tracking down the right theoretical explanation for why jump matters much at all. The long bullets needing more jump probably has to do with the longer ogive radius having to move further to narrow the annular space around the bullet nose as it enters the throat. But I don't know for sure.

[kilotanker22]

CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

Well., I decided to load some more today. I loaded several sets working up a little higher. I also seated the bullets deeper. I shot them all at .120 from the lands today. The best shooting load is pictured below. It was 75 grains of RL 26 behind the 200-grain ELD-X. Just under 1 MOA. Have not measured it yet. Good spread too.

Avg 3054
Hi 3065
Low 3047
SD 7
ES 18.

I can certainly live with this.

[kilotanker22]

Yes I know 75 grains RL 26 is over published max. I worked up to this load from 70 grains via several ladder tests and then in .2 grain incriments. I still have zero signs of pressure. I will probably hang on to this load and tweak seating depth, but for everything I have shot so far. The further away from the lands. The better the loads seem to shoot.

[Unclenick]

Kilotanker22,

Please read this. When you go over book, you need to paste that warning into your post. I'll put it in for you here.

[kilotanker22]

Thanks UN. And understood

[Jsnake711]

I did in my pa-10, I worked up a hunting load using the 165gr sst. And seated at 2.760" with varget and found a node at 44gr. Under a 1/2" I didn't dare mess with seating depth! ...

I just measured my 308 chamber, it measured 2.893" ana im loading those sst's to 2.760". So im way off the lands. Although hornadys suggestion also says the are two nodes with that bullet for seating depth.