Lands question

[leclairk]

I had planned to load .02” off the lands (6.5CM in a factory Savage Model 10) but the rounds won’t fit in my mags. I ended up at .05” in order for the rounds to cycle through the gun. My question is, how close to the end of the mag should I go? Should I go just far enough so that they work in the mag? Also, what do people mean by “jump”?

 

[JMayo]

Yep mags hinder hand loading. Some the tip of the bullet can scrape some it can't. You'll have to figure that out.
That's why mag fed rifles aren't the most popular in score shooting.

Jump is the distance From the lands to the ogive of the bullet.
.004 off the lands is .004 jump.

(Unless I'm confused)

 

[rardoin]

I suggest setting them 0.010" off max mag length and test groups there and successive 0.015" further off in intervals to see where the bullets like it best. You may find a great zone well off the lands. Don't get hemmed in by dogma of having to be close to the lands for best results...do some testing.

 

[Bc'z]

Also look at bullet design.
Secant VLD style bullets will read more jump to the lands.
Tangent style hybrid bullets the ogive is farther forward.
I've learned the same lessons with my
Ruger American predator.

 

[chromatica]

if you want to shoot your long handloads, pick yourself up a Bob-Sled. Its a chunk of delrin machined to take the shape of a magazine. When you insert it into your magwell, the trough in the top surface allows you to single-feed your longer rounds.

 

[K22]

My Remington 700's have a lot of free bore requiring quite a bit of jump. My 223 Rem 700's with a factory barrel is a 1/4 to 1/2 moa rifle with bullets seated about .050" from the lands.

It is generally true that less jump tends to produce tighter groups but this is not absolute with every rifle. In fact, Sierra published an article about this several years ago indicating that some rifles do better with more of the bullet seated in the case thus more jump.

For me being a hunter, the first criteria is to have a round that fits the magazine and will feed reliably. Second, I like to stay about .010" from the lands to prevent a jam into the lands which can raise pressure or cause a bullet stuck in the lands when a live round is extracted. Third, I like to have at least one bullet diameter seating depth to provide adequate bullet tension.

Within reason, I've found that the single most influential factor affecting accuracy is the selection of the type of bullet provided you're using a powder suitable for the caliber you're loading for. I've also found that small variation in seating depth have little to no affect on accuracy but I'm speaking from a precision varmint hunting perspective not a bench rest perspective.

 

[Sandstorm]

You don't actually need a Bob sled..just stick an empty magazine in the action and single feed all day.
Works for me...I never load anything Mag length...or they might fit the mag never tried that.

 

[Bc'z]

You don't actually need a Bob sled..just stick an empty magazine in the action and single feed all day.
Works for me...I never load anything Mag length...or they might fit the mag never tried that.

I wish it were that easy with the Ruger American predator.
It seems to want the upwards angle entering the chamber.