Developing load for new semi-custom

[Bigeclipse]

Guys I have built a semi-custom savage with criterion light varmint 7mm rem mag barrel. I want to attempt to work a load up for it. I have been reloading for 3 years...but only for pistols to save money, not for accuracy. This year I took up loading for rifles for accuracy. I have only loaded for two rifles so far. The first rifle was with little to no guidance except my reloading manuals. So I chose seating depths based off of the manuals, worked up to higher pressure then backed off, and then just tried random powder charges in the safe powder range for my rifle until I got my desired result, which took forever and I knew I must be doing something wrong so I took to the web! I read everything and anything I could. WOW there is a lot of stuff! It is quite OVERWHELMING! Anyways, on my last rifle I did an OCW test which worked out ok. I avoided ladder test because I heard it can give you bad results if you are not a mid level-skilled marksman which I think I am slowly progressing to mid-level but not quite there yet. My goal for this 7mm rem mag is to get me out to 4-500 yards hunting and 700 yards for plinking fun so I would think I would need around a 1/2 MOA rifle.

My first question is what do you all suggest for your testing seating depths?(not sure if you use a different seating method depending on whether you use OCW or ladder test). I know the berger method for their bullets but not sure if that is what you do for all bullets. I will be using 160 grain accubonds for my first test. I am a little hessitant loading to the lands because of the so called pressure spike and also I have not measured my current rifle chamber so I am not sure if it will be even possible to seat that long (I just ordered the bullets). I am on a slight budget, so want to try and avoid shooting 75+ rounds but if that's what I have to do then that's fine. thanks for your help!

 

[Bigeclipse]

Im just wondering where I should start. Again, im not looking for competition loads her...hoping to get around .5 MOA with my new criterion barrel.

Should I simply load .015 off the lands...do my OCW or ladder test and go from there...or should I mimick the berger seating test with a a known safe charge first, then go to OCW/ladder test?

 

[Bigeclipse]

No suggestions?

 

[Punisher]

i start with a mid level load of powder weight. i stik with that powder charge and test group seating depths until you see your group0s tighten. this takes me 9-12 shots. i pick the best one and then ladder test.by raising .2-.3 grains of powder until you see your sweet spot develop on the paper. pick a powder charge in the middle of said sweet spot. then fine tune seating depth if necesarry.

i can usually find a 1/2 moa load within 20 shots. be thurough and patient. let your barrel cool between groups.

 

[Bigeclipse]

i start with a mid level load of powder weight. i stik with that powder charge and test group seating depths until you see your group0s tighten. this takes me 9-12 shots. i pick the best one and then ladder test.by raising .2-.3 grains of powder until you see your sweet spot develop on the paper. pick a powder charge in the middle of said sweet spot. then fine tune seating depth if necesarry.

i can usually find a 1/2 moa load within 20 shots. be thurough and patient. let your barrel cool between groups.

Ok so for that initial 9-12 shots what seating depths are you testing? Berger method... .010 off, .050 off, .090 off, .13 off etc? something else? For the mid-level load powder weight you start with...did you work up to that or do you roll the dice and just test one shot at mid-level powder?

 

[Punisher]

I roll the dice on the powder. Most manuals tell you your max load is 10% under the real max, so by choosing a middle load, I don't feel any danger there. I'm not saying I won't check for pressure signs, but my concern level is nill.

My seating depth method varies on what type of bullet I am shooting. If I'm shooting a VLD, I use berger method. If not, I strt at 20-25 thousandths back from the lands and work away from the lands. Most ogives nowadays seem to like 20-40 thousandths in my guns. But I own zero factory barrels now. All shillen match grades.

 

[Bigeclipse]

I roll the dice on the powder. Most manuals tell you your max load is 10% under the real max, so by choosing a middle load, I don't feel any danger there. I'm not saying I won't check for pressure signs, but my concern level is nill.

My seating depth method varies on what type of bullet I am shooting. If I'm shooting a VLD, I use berger method. If not, I strt at 20-25 thousandths back from the lands and work away from the lands. Most ogives nowadays seem to like 20-40 thousandths in my guns. But I own zero factory barrels now. All shillen match grades.

ah ok thanks for the info. The barrel on my rifle is a criterion match grade savage prefit. I guess I will try .020 off and go from there. do you go .020, .030, .040...or do you take smaller steps....020, .025., .030 etc?

 

[RobG5589]

Guess I will jump in with my first post. Seating depth depends on the bullet and chamber. Hunting style bullets can generally tolerate "jumping" where as a vld style target bullet may like to be near or at the lands. Did you have your chamber set up for a specific bullet or just a standard cut? I have run factory 700 chambers, which are notoriously long, with a bunch of jump and still produced great accuracy. We are talking something like .100+ off.

I would contact the bullets manufacturer for seating depth help if you cannot find it elsewhere.

My point is, do not get caught up in a number. Start somewhere in the middle and go from there.

For myself, I do not use OCW or laddering. I simply load with a starting powder load and depth based on research and go from there. Never had a problem doing it that way, although I can see the benefit to ocw and ladder testing. I also test at 300 yds. 100 yds simply isn't far enough to gain what I consider to be useful data.

Based on what you wrote, your inexperience says to stick with "book" data until you gain some experience to venture into the unknown. Start with the book 3.245 oal and see how she shoots.

Good luck and be safe.

 

[Bigeclipse]

Guess I will jump in with my first post. Seating depth depends on the bullet and chamber. Hunting style bullets can generally tolerate "jumping" where as a vld style target bullet may like to be near or at the lands. Did you have your chamber set up for a specific bullet or just a standard cut? I have run factory 700 chambers, which are notoriously long, with a bunch of jump and still produced great accuracy. We are talking something like .100+ off.

I would contact the bullets manufacturer for seating depth help if you cannot find it elsewhere.

My point is, do not get caught up in a number. Start somewhere in the middle and go from there.

For myself, I do not use OCW or laddering. I simply load with a starting powder load and depth based on research and go from there. Never had a problem doing it that way, although I can see the benefit to ocw and ladder testing. I also test at 300 yds. 100 yds simply isn't far enough to gain what I consider to be useful data.

Based on what you wrote, your inexperience says to stick with "book" data until you gain some experience to venture into the unknown. Start with the book 3.245 oal and see how she shoots.

Good luck and be safe.

I have been reloading for pistols for years to save money on shooting but just recently started loading for rifles for accuracy. So although I am new to rifle loading and accuracy, I do not consider myself a complete newbie. Ive just read so much on many different thoughts of how to reload. Just wanted to know what the guys on this site do for a starting OAL. I have been collecting all the appropriate tools, comparators, lock and load headspace gauges, etc. Just did not know a good starting point for length but thanks for your opinion.

P.S. the barrel is not set-up for specific bullet. Im guessing it is a standard cut since it is a savage prefit made by criterion.

 

[RobG5589]

I would start with a standard oal with a factory chamber and go from there.

 

[backwoods83]

Accubonds have a tangent ogive so they are not finicky. Put them .030" or .060" off the lands, load 5 with 68grns of H1000 and get your 100 yard zero, then load from 68-72.8grns in .4grn increments using Fed215s or CCI 250s, then use a 1" bullseye @ 300 yards to do your pressure ladder. Use a powder charge in the middle of your 3 or 4 closest shots. After you pick your charge weight shoot a 4 shot group at 100 yards and a 4 shot group at 300 yards. 26 shots should put you under 3/8 moa easy with a CBI barrel.

 

[Bigeclipse]

Accubonds have a tangent ogive so they are not finicky. Put them .030" or .060" off the lands, load 5 with 68grns of H1000 and get your 100 yard zero, then load from 68-72.8grns in .4grn increments using Fed215s or CCI 250s, then use a 1" bullseye @ 300 yards to do your pressure ladder. Use a powder charge in the middle of your 3 or 4 closest shots. After you pick your charge weight shoot a 4 shot group at 100 yards and a 4 shot group at 300 yards. 26 shots should put you under 3/8 moa easy with a CBI barrel.

the powder i have for my first test loading is imr7828ssc with CCI250s, but I may give your method a shot other than powder. I know it can differ between guns and velocities but what kind of vertical separation between shots can you expect at 300 yards with .4grain increments?

 

[backwoods83]

Once you find the sweet spot, the 3 or 4 closest shots, 1.2-1.6grns, there will be almost no vertical dispersion usually less than 3/4" for 3 shots or under an inch for 4 shots. If you are using winchester or remington brass start at 64grns with Imr7828 ssc and work up to 68.4-68.8grns. Yes that is over listed max but 7mm rem mag data is very anemic, 61k psi vs 64-65k psi of every other belted magnum which has 375 H&H roots.

 

[Punisher]

I think .010 Increments are fine. I don't know if you have a comparitor, but that is going to give you the best info on length to ogive. I have a micrometer for this, but it is pricey!