Question about preparing for a ladder test

[tepeter1]

Gentlemen

I have an FN SPR build using a Bartlein 20" 1-11.25 twist 5R barrel. The chamber is a Lapua chamber based on a round that was sent to the rifle builder. That round is Lapua Brass with a berger 155 VLD shoulder bumped .002, COALof 2.820 with 0.047 free bore. I have just finished setting up my reloading station using redding competition dies and have a few questions about prepping for ladder testing.

In my research on ladder testing it is normally recommended to use factory ammo to get your 300 yd zero and then to run through your ladder test with the least recommended charge weight to your highest.

I have two issues.

1. This rifle has only had one round fired from it for a fouling shot. I just received my USO SN3 last week so I don't even have a 100yd zero.

It is my intention to use handloads instead of factory loads to get my 100yd zero and then my 300yd zero with the minimum recommended load of Varget which is 40.0 grains. Is there anything wrong with this idea, or am I overanlyzing this issue?

2. Should I begin this ladder test and load development with the rounds loaded to 2.820 COAL and watch for pressure signs as I progress through the ladder test? My thinking on this is that since the bullet will be closer to the lands I will determine right out of the gate what the maximum safe load charge will be.

I think I gave enough information for some educated input from all of you; however, if I didn't I will add information as requested. I would appreciate any input from those of you who take the time.

 

[Kentucky Jelly]

Re: Question about preparing for a ladder test

I wouldn't be concerned with a zero as long as you are on paper at 300. I bore sight and go with it as long as it is on paper. I use large targets though, and that helps.

 

[fockell]

Re: Question about preparing for a ladder test

You need to get a load worked up first. You need to have a good idea of how well of group you and your rifle can do to get the most out of your test. If your load combo is shooting 3 moa, likely not but if it is shooting that poor you will think your scope is all over the place. Enjoy your new rifle.

 

[vman]

Re: Question about preparing for a ladder test

If this were me I would do the following.

Go to the range with about 50 virgin cases loaded up. Im assuming the brass is brand new?

I would zero in the scope, determine the drop at 300 etc etc.

I would clean the rifle after a few rounds, and finally again at 40 rounds.

I would use the last 10 rounds to season the bore again and keep it fouled.

I would then load up a standard ladder using those 50 fireformed cases, shooting from lowest to highest, using the same point of aim and the best shooting form i can possibly do.

 

[Headgear]

Re: Question about preparing for a ladder test

+1 to the Vman.

I just got some new Lapua and ran a new test for it. I first full length sized and chamfered virgin brass to test. I noticed the seating pressure of them was all over the place. The results from them were inconclusive. I also reloaded five that I shot out in the back yard just to check for pressure. They were neck sized. The seating pressure was a hell of a lot more consistent and I was surprised at the resulting test using them.

I was shooting at 300 yards at a 2" orange bull with a half inch black diamond canter. 44.4 hit the bottom at 6:00, 44.8, 45.2 and 45.6 were all stacked in the diamond with a little horizontal shift but all touching and 46.0 was at 11:00 at the top of the circle. I'm not sure if fire forming or neck sizing or both were responsible but the difference was real.

I had twenty rounds of 45.2 that I brought for sighters etc. and had thirteen left over so I shot two, five and one three round groups. One of the fives was just over 1/2 MOA, one was just under and the three shot group were all most touching each other so I new my shooting was good and the conditions hadn't changed.

Now that I have fifty or so fire formed brass, I am going to try it again next weekend to see if I get the same results. I am going to do it again with virgin vs the fire formed just for the shits and giggles of it. If the weather holds out, I let you know what happens.

 

[ChadTRG42]

Re: Question about preparing for a ladder test

+1 for what's stated above. Load up 4-6 rounds for a few barrel break-in and cleaning. During this cleaning, sight in the rifle at 100. Have a few rounds down the barrel for fouling shots and use these fouling rounds for getting on paper and on target at 300.
Next, don't mess with the ladder test- do an old school load work up. There's no point in starting with 40 grains of Vargay, unless you want a slow 308 round. Do a little research here on the hide, and start a little lower than some recommended loads and work up in small increments.