30-06 Length for Savage - Short(ish) Chamber?

TX_Diver

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May 27, 2019
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Being home sick the last few days I finally got some time to load up some rounds for a Savage 114 American Classic - Stainless in 30-06. 22" 1:10 barrel.

While trying to determine a starting point for COAL/CBTO I ended up with the rounds significantly shorter than I thought they'd be and am wondering if I'm going to run into case capacity issues (planning to use H4350 or IMR 4350).

I have 1x LC 62 Match Brass from a member on here. I FL sized, trimmed to 2.484-2.488 w/ a WFT, uniformed and cleaned the primer pockets, and chamferred/deburred the necks.

Bullets to test are 180gr Nosler Accubonds, 175 Sierra TMKs, and 178 Hornady ELD-Ms. Plan was to load a ladder of each, find a decent velocity, then shoot some groups with each and go from there.

The details:
My savage magazine length is ~3.5" w/ SAAMI Max COAL being 3.34". My plan was to start at a COAL of ~3.5 and work backwards til I found a length that would chamber without the bullet contacting the lands. To do this, I just kept seating the bullet in the press until I could close the bolt, then once I could close the bolt and extract the round without needing to push it out from the muzzle, I'd coat the bullet w/ sharpie and keep seating it further til I didn't get any marks on the sharpie from the rifling or chamber. This worked fine on my T3x in .223 but I haven't done it w/ other rifles before.

Quick summary w/ full results below:

at 3.5" COAL nothing would chamber and I couldn't even close the bolt.
at ~3.34" COAL (I started measuring CBTO once I got inside mag length) -
3.34" COAL / 2.704" CBTO - Accubonds would chamber but there was still some contact between the bullet and the chamber
3.34" COAL / 2.706 CBTO - 178 ELD-M would not even chamber
3.34" COAL / ~2.614 CBTO - 175 TMK - Would chamber but there was light contact w/ the bullet/chamber still

Once I got down to the ~2.6" CBTO all 3 would chamber (some w/ light pressure still on the bolt) It wasn't until I got to ~2.53" CBTO that I could chamber a bullet w/out getting a mark on the sharpie. At one point I marked each case on 4 sides and started loading them in the same orientation every time... Looking from the top down, the TMKs always had a mark on the left, the accubonds had a mark on the right, and the ELD-Ms would get a mark 360 degrees until the very end when it was marked on the bottom. I tried chambering and ejecting the rounds w/ the rifle in different orientations, and ejecting rounds slow/controlled to prevent contact w/ the action also and had no change of results. The only factory loads I have to compare to are 180 partitions and they are ~2.6" CBTO but don't get any marks when coated w/ a sharpie...

I haven't actually charged any cases yet and shot, but am thinking that I'm going to run into case capacity issues if I'm at 2.53" CBTO as this basically has the ogive of the bullet just past the lips of the case. The TMKs are definitely on the long side.... Ultimately we're talking about less than 1/8", but it still just seemed odd that at SAAMI max case length I can't even get the ELD-Ms to chamber.

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Each case was identified and the sides marked 1-4 relative to the side that I put up in the mag

So am I overthinking this? Run at ~2.6" CBTO and start testing charge weights/velocity? Or should I pay attention to the marks that I'm seeing on the sharpies and start back at ~2.5" CBTO even though that puts me so far under the SAAMI COAL?

For reference at 2.53" CBTO the COALs are as follows:
175 TMK - 3.25"
178 ELD-M - 3.167"
180 AB - 3.157"

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T

TX_Diver

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Also I have a hornady modified case and oal gauge ordered now after all that (something about using the right tool for the job…) But was curious as to see if anyone had other ideas in the mean time…
 

Pickettpuncher

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Each bullet will have its own measurement. Keep that in mind while doing this. You can get close using a cleaning rod. Have bolt closed. Run rod till you touch the bolt. Make sure you’re not on the ejector. Mark rod. Drop bullet into barrel. Hold it there, a pencil works good. Run rod till you hit the bullet. Mark it. Measure your distance. This will get you COAL. Make sure when doing this you note what the COAL is as well as the BTO.
 

Lawnboi

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Being this is not your fired brass I’d first make sure brass isn’t the culprit to the hard closing.

After that I’d use the comparator for each kind of bullet and find where it jams. Measure the guage piece of brass for headspace as well and see how it compares to your once fired sized.
 

HiMtnHntr

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It's a good idea to use the OAL gauge to determine max cartridge length for each bullet. If you're going to fiddle with cartridge length right off, do so at min charges and go from there.
 

sndmn11

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My vanguard and Tikka both are about 2.69" to the lands using the Hornady gauge and any bullet. Seems yours is close to that.
 

Jasent

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Jan 15, 2022
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If it does end up being way short after you use the comparator then you could rent a uni-throater and extend your lans out to where you like it. It’s a very simple task
 

Vern400

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Aug 22, 2021
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Each bullet will have its own measurement. Keep that in mind while doing this. You can get close using a cleaning rod. Have bolt closed. Run rod till you touch the bolt. Make sure you’re not on the ejector. Mark rod. Drop bullet into barrel. Hold it there, a pencil works good. Run rod till you hit the bullet. Mark it. Measure your distance. This will get you COAL. Make sure when doing this you note what the COAL is as well as the BTO.
This is a method that always works. The number you get is the contact (or jammed) seating depth. If you're good at measuring the rod never lies. I have this data for every rifle and bullet combination written in my reloading book.
 

Vern400

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Aug 22, 2021
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Be happy. Lots of rifles have so much free bore you have to single load cartridges to get bullets close to the lands. I've remachined barrels to pull the lands CLOSER to the bolt face.

You're using heavier than design bullets. Meaning 30-06 is kinda sorta intended for 165 gr bullets. If you consider the first 110 years of history anyway. It's not really a surprise. On average bullets have gotten more "pointy" so at least your mag works.
 
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