First time loading off the lands

[callen3615]

Just loaded up a few rounds for my 700 sps in 308. I usually load 175 smks with 42.4gr of 4064 at 2.8 OAL. I have been wondering if I can shrink my groups if I load off the lands. Here is how I determined my headspace.

Took a fresh piece of brass that had been necksized. Seated a 175smk barely in the case, then chambered that round. Noted the OAL (I dont have a gauge). 2.950 is the number I came up with.

I repeated this several times and only got smaller numbers, I assume the largest number was the most accurate and the smaller numbers came from me either repeatedly chambering the same cartridge or chambering the test cartridge too hard.

2.950 was my largest number, I came up with numbers around 2.940 to 2.935 after repeatedly chambering the same round.

Next I tweaked my bullet seating die until it would consistently seat at 2.935. So now my handloads should be .015 off the lands correct?

I used the same charge, 42.4gr. I assume I shouldnt have an increase in pressure by increasing my OAL, correct?

Just checking to make sure I did this right. I can always pull em and change the OAL.

 

[0311@LAR]

Re: First time loading off the lands

Get your self a Hornady OAL guage and a comparator tool. I tried to get my over all lengths like you are doing now and it drove me nuts. Could never get consistent measurements. After I bought the two for mentioned tools, it made life easier.

 

[varmint slayer]

Re: First time loading off the lands

Best way I know to do it without getting a Hornady OAL gauge is to seat a bullet long like you did except color the ogive area black with a marker and then chamber the round. You should see where the marker rubbed off a bit where the ogive is contacting the lands. Keep seating and re-clambering until you don't any marks on the ogive. The reading just before the marks disappear I consider just touching the lands and everything after that off.

 

[callen3615]

Re: First time loading off the lands

I did mark 4 lines about .03 apart from each other on the bullet so I could visually inspect how consistent it was. I will get a OAL gauge soon, I will load some at 2.935 for awhile and see how they shoot. Then I may start bumping them back .01 and see if it improves or not.

Thanks for the help.

 

[armorpl8chikn]

Re: First time loading off the lands

SMKs in my experience don't like touching the lands. The magic number I have always found was AT LEAST .015" off the lands. More doesn't matter if your load is right.

 

[armorpl8chikn]

Re: First time loading off the lands

If you are trying to get every round EXACTLY .015" off the lands don't bother. If your load is right and they vary from one to the other it won't make any difference. Just get them to an average.

 

[callen3615]

Re: First time loading off the lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: armorpl8chikn</div><div class="ubbcode-body">If you are trying to get every round EXACTLY .015" off the lands don't bother. If your load is right and they vary from one to the other it won't make any difference. Just get them to an average. </div></div>10-4

 

[MitchAlsup]

Re: First time loading off the lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cpt. obvious</div><div class="ubbcode-body">I repeated this several times and only got smaller numbers, I assume the largest number was the most accurate and the smaller numbers came from me either repeatedly chambering the same cartridge or chambering the test cartridge too hard.

2.950 was my largest number, I came up with numbers around 2.940 to 2.935 after repeatedly chambering the same round. </div></div>

Between each cahmmbering, you need to push the bullet back out to OAL=3.000. So that your chamber is doing the same thing every time.

 

[timelinex]

Re: First time loading off the lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: armorpl8chikn</div><div class="ubbcode-body">SMKs in my experience don't like touching the lands. The magic number I have always found was AT LEAST .015" off the lands. More doesn't matter if your load is right.
</div></div>

I have mine .01 INTO the lands, and it's an accurate load.... That was the most accurate out of my testing.

Honestly though, get a gauge. Even with the gauge it's insonsistent and can drive you crazy. Without the gauge it's super inconsistent like u said, to the point tht it's not reliable. If you are dead set on not using a gauge then take a lighter to the bulls and char it till it gets a black film. Seat the bullet farther and farther till you get a mark on it from the lands. That is roughy where your lands are. You really don't need to know more specific, just seat it .01 farther than that and do a couple loads seated farther and farther from the lands . Let the results dictate which distance to choose. You might not know exactly how far from or into the lands you are , but the results on paper are the same..

 

[callen3615]

Re: First time loading off the lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: timelinex</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: armorpl8chikn</div><div class="ubbcode-body">SMKs in my experience don't like touching the lands. The magic number I have always found was AT LEAST .015" off the lands. More doesn't matter if your load is right.
</div></div>

I have mine .01 INTO the lands, and it's an accurate load.... That was the most accurate out of my testing.

Honestly though, get a gauge. Even with the gauge it's insonsistent and can drive you crazy. Without the gauge it's super inconsistent like u said, to the point tht it's not reliable. If you are dead set on not using a gauge then take a lighter to the bulls and char it till it gets a black film. Seat the bullet farther and farther till you get a mark on it from the lands. That is roughy where your lands are. You really don't need to know more specific, just seat it .01 farther than that and do a couple loads seated farther and farther from the lands . Let the results dictate which distance to choose. You might not know exactly how far from or into the lands you are , but the results on paper are the same.. </div></div>

Im gonna try that.

I just shot my rounds that I seated just off the lands.

I shot 10rds of my normal 2.800 OAL, horizontal dispersion was great but it strung them vertically. About 1 inch vertical dispersion, pretty much 4 rounds stacked vertically with 1 going through an existing hole.

Next I shot my 5 rds that I loaded off the lands. Those grouped much better. vertical dispersion was negligible, horizontal was around .306. Group size came out well under 1/3rd of an inch, hell under the diameter of my bullet.

I wish I had loaded more, kinda thinking that was a fluke.

Id like to load more at that OAL and see how they do in the future, may try the lighter method.

Thanks

I

 

[RampedRaptor]

Re: First time loading off the lands

Cheers!!!

 

[UrbanSi]

Re: First time loading off the lands

Universal expanding die, flare the case enough so you can almost pull the bullet out by hand. Close the bolt, pull bullet...repeat

People want to make something easy like this hard, the Hornady tool is kind of junk, you would be better off doing the old cleaning rod trick.

I never had good luck with my 700 just closing the bolt on a necked case, very inconsistent. If you can pull/close the bolt and get the same measurement 10 times you are on to something.