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Old January 20, 2018, 12:35 PM   #1
308Loader
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new 308 COL

hello all, I picked up a new 308 and was measuring the distance to the lands with a hornady OAL gauge and found the lands of the new rifle to be much shorter than the old one. Not too surprising I guess, my question is can I just reseat some already made rounds to the new length? I'm using a mild load of 40.5g of 4064 and 168 gr HPBT bullets, no crimp. With the old rifle their OAL using comparator is 2.282. New rifle with same bullet lands start at 2.205. what would be a good OAL to start at?
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Old January 20, 2018, 02:16 PM   #2
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You should be able to, sometimes if they have been seated fro some time they start to stick to each other.

I do it all the time with new rounds. I set some at what I want to work with to start with, the rest of the test loads long and then move them back to see what difference I can detect.

That said, I have also found that the Hornady comparator measure at least
.010 shy of sticking in the lands.

If I just use the comparator I usually move them out another .010 - give me a possible .020 which is a good start point.

Best to nail it down is an unloaded and resized case with your bullet choice in it seated .040 longer than the comparators says.

Put it in, very gently move the bolt forward, the bullet most likely will stick before its closed (Nossler is the only one that does not stick I have tested)

Tap the handled back with a screwdriver handle, then set the bullet .010 deeper and try again.

Repeated until the bolt closes and you gently try to turn the bolt handle down (it may stick partway down) - set back another .010.

At that point you are no more than .010 and likely .005 off the true lands.

Gives a solid baseline for reloading as well as future throat wear.
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Old January 20, 2018, 02:50 PM   #3
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0.010" is the usual jamming distance recommended for loads intentionally seated into the lands, and is where the bullets really start to stick, so your comparator result makes sense, though this can vary by chambering and throat angle some.

I've pulled a lot of old cartridges down, and where there is cold bonding between the bullet and case, seating the bullet slightly deeper to loosen it for pulling is the usual recommendation. The case is pretty strong in the insert direction, so seating deeper should be fine.

That 0.077" difference is about the freebore difference (0.075") between a 7.62 NATO chamber and .308 Win match chamber, according to Clymer's numbers. What are the rifles involved?
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Old January 20, 2018, 04:57 PM   #4
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Your using the same load , powder & I'm stopping the Sierra 168 HPBT MatchKing . Also used the Hornady OAL gauge , gets you in the ballpark . No problem reseating your seated rounds deeper. What is your new rifle ? If your new rifle is a bolt action an you can strip your bolt to just the bolt housing , I find it more accurate by feel for case headspace , base to datum & base to ogive measurements . Has to be checked with every new lot of bullets . Hope I helped .

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Old January 20, 2018, 05:15 PM   #5
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The old rifle that I several hundred rounds loaded for is rem 700p 26" 1 in 12 twist. Even at 2.282 their is quite a bit of freebore, don't remember off hand how much. To get the bullet into the lands with that one their wouldn't be enough bullet in the case. This rifle and load combo shoots really well for me. The 700p is at about her 6000 rnd ct still shooting sub MOA. The new rifle is savage model 10-t-SR 24" 1in 10 twist. My first ever savage, just got back from the first ever range day with that one. Found some FGMM and PPU in 168gr and some 175's in my factory ammo can to shoot today. I would suppose I should just work up another load for the new rifle and keep the rounds separated. Was asking about reseating for range fodder to break in the barrel and rough sight in. The jury is still out on the mod 10-t-sr, she definitely isn't a 700p, not bad though.
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Old January 20, 2018, 05:34 PM   #6
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"Has to be checked with every new lot of bullets."

Yes for sure. I'm shooting hornady 168gr HPBT, recently picked up a new lot of bullets that were way different than the old lot. Made me scratch my head for a min when checking OAL with comparator and where I had my seating die set too for the previous lot.
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Old January 20, 2018, 06:55 PM   #7
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My rifle started out as a Reminder.700 LTR , changed the trigger to a Jewell set at 10 ounces , only used for benchrest shooting . Changed the HS stock the the longer stock that comes with yours 700P .After 4000+ changed the barrel to a match grade Rock Creek M24 5R rifling 1 in 11.27 twist completely blueprinted & bedded . Love the rifle but just like your 700P had so much free bore just left the OAL at 2.800 an worked with powder charge . With the new barrel hardly any free bore . With the Remington I removed the extractor plunger spring , installed a very light spring , plunger is just alittle over flush . The case does not eject , make it easier to get the case , doesn't fly out . This makes it easy to set the headspace & ogive . With Savages they have much less free bore then Remington's. I have my rifle with .0015 headspace and .002 jump . I like barrels with less free bore , we're both loading on the low side with IMR 4064 fills the case even with a low charge . We're I live the out door ranges are 200 yards . That's the distance I only shoot . Savage is putting out very accurate rifles , alot of my shooting friends have Savages . I also tried Hornady A-Max 168's shoot mostly Sierra 168 MK. The bolt face on the Savage floats , I don't think you can check headspace & ogive settings by feel like with Remington. Good Luck with your new toy .

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Old January 20, 2018, 07:13 PM   #8
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Forgot to ask are you neck or full sizing your brass . I'll try to keep my answers shorter , have a tendency to ramble on .Sorry

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Old January 20, 2018, 09:42 PM   #9
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The Savage boltface lines up with a headspace gage's head surface. It's how you set headspace on those rifles: a headspace gage and barrel vice and barrel nut wrench. It takes a short gage to compensate for chamber draw; that or a little ingenuity with a GO gage and turning the barrel threads just enough to compensate.

The Remington's are famous for their long throats. It keeps pressures down, but they may have decided it helps barrel time. They do well on accuracy without getting ogives close to the throat. A Timney trigger is a good investment to avoid the whole Walker trigger issue.
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Old January 21, 2018, 11:26 AM   #10
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so with my measurements using the hornady tool I measured the same bullet in the bore 10 times and averaged them out to 2.205 to the lands, then I subtract .020 and get 2.185. That is where I should seat to for the .020 jump that I see most people going for correct? That gives me a OAL from tip to head of 2.825, smidge over book. chambers good in new rifle, no marks on tip of bullet... think ill try it out today.

cw308
I get my brass from the range, once a year they sell all the collected brass for a buck a pound. when I get it all cleaned up I SB-FLRS, never know if it was jerked out of a simi auto, or shot from a wonkey chamber. once it has been shot out of my rifle I usually FLRS to SAMMI spec. I have played with neck sizing some didn't find a whole lot of advantage, mind you I'm not neck turning or using a collet die (yet). long story short, all the loaded ammo I currently have is FLRS shouldn't be a issue swapping between chambers.
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Old January 21, 2018, 01:09 PM   #11
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You probably can but why would you? Two different rifle's that could likely not shoot the same load well. I'd pull what I have and load for the new rifle!
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Old January 21, 2018, 02:06 PM   #12
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You could be oversizing your brass . I size my brass using the standard RCBS F/L die with the expander ball , l don't neck turn my brass either. Why wouldn't you size your brass to the chamber of each rifle , your brass will last longer , get better accuracy . The Hornady OAL Gage measurements are off the case shoulder. More accurate knowing the distance from the case head to datum line ( shoulder ) then finding the distance from the case head to the ogive line to the rifling. Then accurately be able to jump or jam your rounds.
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Old January 21, 2018, 02:26 PM   #13
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"...the lands of the new rifle..." You can have another rifle that has the next S/N after your rifle and it'll be different. In any case, the whole off-the-lands stuff is done after working up the load. And only if you feel like fiddling with it. It's not necessary at all. It's just a load tweaking technique.
"...lands start at 2.205..." Highly unlikely. OAL is not measured to the ogive and the OAL for a 168 is 2.8".
40.5 of 4064 is a 1 grain tick below current minimum for 168 grain bullets. Not enough to matter, but you need to work up a load for the new rifle anyway. No two will shoot the same ammo the same way.
"...get my brass from the range..." Not good for accuracy. You have no idea what or how many times has been done to that brass. S'ok for hunting loads, but a 168 grain match bullet will shoot better out of brass that you know exactly everything about it.
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Old January 21, 2018, 02:53 PM   #14
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Don't get me wrong on the reseating thing. I know I need to work up another load for the new rifle. The idea was, as I stated before to make some quick range fodder to "break in" and rough site the new rifle, really just to go shoot the darn thing. I don't keep much factory ammo around and the stuff I have loaded is too long for the new rifle. being that I'm on the low end of the charge weight (witch shoots fine for the distance I shoot) and all is in book speck, it seemed easy enough to just push the bullet in a little more and go shoot some. Turns out it worked just fine, clover leafs and a couple holes in holes at 100yrds. I'm sure I can work up a better load just didn't have time to sit at the reloading bench this weekend.

"...lands start at 2.205..." Highly unlikely. OAL is not measured to the ogive and the OAL for a 168 is 2.8".

Isn't the idea of using a comparator to measure OAL from the ogive rather than the tip that is inconsistent from bullet to bullet? 2.205 is with comparator, not true OAL. Yes I see that the book shows 2.8 tip to case head. Using the comparator - .020 I come up at a little over that but know that I have some jump built in.

"I'd pull what I have and load for the new rifle!"

Not retiring the old one just yet. I want to keep some ammo I know shoots well for her still.

"Why wouldn't you size your brass to the chamber of each rifle , your brass will last longer , get better accuracy"

First time I've had another rifle in same cartridge/cal. Sizing for a particular chamber is something I need to work on. SAMMI or case gage specs seem to work ok, but I do see the advantage to this.
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Old January 21, 2018, 04:02 PM   #15
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308Loader,

Mr. O'Heir doesn't appear to understand you are referring to your bullet comparator's value instead of COL with your short numbers. This is not the first thread in which he's proven to be confused by this. Don't worry. You have it right.

Your mixed brass may have some military that's a little tighter than a Winchester case, but for Winchester brass, Hodgdon's starting load with the 168 Grain MatchKing is 41.5 grains of IMR4064, and Federal's match ammo with that bullet uses 43.5 grains of 4064 in a case that is almost as heavy as military. Because you are below Hodgdon's starting load, you could safely jam the lands.

If I were in your shoes, here's what I would do, modeled after Berger's method, but with a little bit shorter steps for the smaller ogive radius bullet you have. Seat 30 rounds to 2.215", 30 rounds to 2.190", 30 rounds to 2.165" as measured on the comparator. This will give you 0.010" jam, 0.015" jump, and 0.040" jump, respectively. I would also set up twelve more at Hornady's recommended 2.800" COL to use for fouling shots.

Set up 3 targets side-by-side, run the first two foulers through a clean bore, and then start shooting the others round-robin style. That is, one 2.215" round on target 1, cool for your normal expected time between shots, fire one 2.190" round on target 2, cool, and then one 2.165" round on target 3. Go back to the long round and target 1, a middle length round on target 2, and a short round on target 3, cycling through that over and over again. Clean every 15 rounds (6 on each target), followed by two more foulers, and repeat. If you don't get through all 90 record shots the first day, stop at 30 or 45 (any cleaning point) and take the target home and go back to continue with the next target on the next range day.

In the end, you will have 30 round groups for each seating depth. The round-robin method ensures the different loads "shared" the same conditions and temperatures and light pretty evenly, and the same firing rhythm. By cleaning at 15 rounds instead of 18, you rotate the post-clean starting target so the effects of cleaning don't bias one target over another. 30 rounds will give you a very statistically solid evaluation from which to see which seating depth worked best. If it is 0.015", then going to 0.020" won't make an appreciable difference. Neither will later-on using 2.800" instead of 2.795". You just want to work up the powder charge over again at whatever seating depth looked best.
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Old January 21, 2018, 05:29 PM   #16
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Thanks nick, I might have some time this week to try that out.
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