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Modifying factory ammo

Submarine Sharpshooter

Submarine Sharpshooter

Bun Butterer
Minuteman
Mar 22, 2021
55
34
Honolulu, HI
I’ve got to field a question to reloaders with a better depth of experience than mine

I ordered some .308 sight unseen (ammo game is cut throat, especially when you live in Oahu) and the vendor failed to mention the rounds are over SAAMI specified COAL (see attached image). They’re for a small frame AR10, so that’s a problem.

Calipers are telling me they’re 2.91 inches and I need to get them down to ~2.87 to fit in an SR-25 mag. Should I just toss them in the press and seat them a little deeper? Shaking the round produces a readily audible pepperbox sound so it seems like there’s room in the case - very scientific I know.

If the consensus is no, I guess I’ll just be doing surgery on all of them, NBD, but I’m low key stressing as these are potentially my elk hunting rounds and associated lead up practice rounds for all of 2021.
 

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The only tricky part is getting consistent results from the same bump. It depends on the consistency of the ammo; neck tension, friction between bullet and neck, and seating depth,. The smaller the bump the more those other factors come into play. Not sure how important this is to you. For an AR this wouldn’t worry me even a little bit.
 
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Submarine Sharpshooter said:
I’ve got to field a question to reloaders with a better depth of experience than mine

I ordered some .308 sight unseen (ammo game is cut throat, especially when you live in Oahu) and the vendor failed to mention the rounds are over SAAMI specified COAL (see attached image). They’re for a small frame AR10, so that’s a problem.

Calipers are telling me they’re 2.91 inches and I need to get them down to ~2.87 to fit in an SR-25 mag. Should I just toss them in the press and seat them a little deeper? Shaking the round produces a readily audible pepperbox sound so it seems like there’s room in the case - very scientific I know.

If the consensus is no, I guess I’ll just be doing surgery on all of them, NBD, but I’m low key stressing as these are potentially my elk hunting rounds and associated lead up practice rounds for all of 2021.
Click to expand...
What is this factory ammo?
 
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I wouldn't hesitate to seat them to where you need. You're only talking .004-.005. Just to be cautious I might start by seating 1 or 2 and shooting them and looking for pressure signs. That is, if the bullets are not crimped.
 
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lightman said:
I wouldn't hesitate to seat them to where you need. You're only talking .004-.005. Just to be cautious I might start by seating 1 or 2 and shooting them and looking for pressure signs. That is, if the bullets are not crimped.
Click to expand...
Not quite. He's talking about bumping them .040", not .004"
 
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To be cautious:
Single load and fire one for function. If it's close to the lands you may have pressure signs anyway.

Bump a couple back .02 then in .01 increments til you get where you want checking along the way.

Curious which "Factory" ammo this is. What is your bullet weight, make, etc?
 
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I’d second some of the advice you’re seeing: if you can single-feed and get functional fires, bump the bullet deeper by 0.010” and try again. Keep going, watching closely for pressure signs. If you get to your goal without issues, great! If not, sorry boss. Maybe a mag that allows longer COAL in that case?
 
Identify the components. If the powder is known, then a better informed decision can be made. That said, what you got seems like something that might grenade your rifle. If I got fucked like that I would take it all apart and do over.
 
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MinnesotaMulisha said:
Have you made contact with the vendor and asked why they are selling 308 ammo that isn't to SAAMI specs?
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SAAMI specs are voluntary, not mandatory.

2.91 will fit and work perfectly in Palma-chambered single-shot bolt action 308s. A potential elk-hunting round is probably going to have a heavier bullet that will function in an internal-magazine bolt action. Factory 700s generally have long throats, so a long-seated bullet will just be kissing the lands for best precision.
 
Back in the day match shooters would take M118LR and seat the bullet deeper to break the sealant bond between the bullet and neck. It was believed to give more consistent velocity. They would also make "mexican match" in 30-06 and 762 - pull the Ball bullet and stuff a Match King back in the case.

That said, you could count on what components went into those rounds and knew the deeper seating was not an issue pressure-wise.

I'd pull the bullet on one, see what you are dealing with as far as case fill/compressed load or not, and based on favorable results from that, go ahead and seat them a bit deeper.
 
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I have shot more than a few Mexican Match rounds during my lifetime.

Were I you, I would pull the bullets first so as to break the crimp or neck tension, then re-seat them to the depth you want and try them out, a few rounds at a time.
Sometimes the rounds I was wanting to alter had such a tight crimp or bullet to case adhesion that when I tried to push them in a bit the shoulder would bulge a bit, rendering them unusable. After a failure, or 28 or thereabouts, I pulled every one , then, re-seated them as to where I wanted them.
Worked for me. FM
 
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Halfnutz said:
To be cautious:
Single load and fire one for function. If it's close to the lands you may have pressure signs anyway.

Bump a couple back .02 then in .01 increments til you get where you want checking along the way.

Curious which "Factory" ammo this is. What is your bullet weight, make, etc?
Click to expand...
It’s Winchester loaded with 155.5gr Bergers. It is 100% factory ammo purchased directly from Midway USA. I thought it looked a little out of spec / long when it arrived (visiting family in mainland because midway doesn’t ship to Oahu).

Within the last week Midway has added a banner - way at the bottom - warning of being loaded outside SAAMI standard. I’m strongly considering contacting their CS and trying to get my money back, as buying five hundred dollars of factory ammo that turns into a handloading project right out of the gate is unsat. Right now I believe plan A is to sell it to fund new ammo and that plan B is Mexican match.


KnowNothing256 said:
I’d second some of the advice you’re seeing: if you can single-feed and get functional fires, bump the bullet deeper by 0.010” and try again. Keep going, watching closely for pressure signs. If you get to your goal without issues, great! If not, sorry boss. Maybe a mag that allows longer COAL in that case?
Click to expand...

We’re thinking the same thing with respect to the last line, I have KAC M110 mags that get you to 2.875ish, as opposed to the commercial standard of 2.8 you get with most AR10 mags

also, thank you to everybody that dropped in for your input - sincerely, it is appreciated
 
First off, do you actually have a problem to fix? Will the rounds chamber and extract? Yes; no first problem to fix.

No? shorten .002-.003 at a time and repeat test #1. When (if) it will chamber and extract, shake it to see if the powder is still relatively loose inside the case. No; go no further.

Get your courage on and fire one. If no mishap; examine the fired case for overpressure signs.

There could be some peril associated within this step, some sandbags over the action and a string for the trigger may be advisable, if you're that concerned. You can easily choose not to do this, so I will not assume any responsibility for mishaps.

This fired case inspection is a really important step, so get second opinion(s) from (an) experienced reloader(s). If they agree it's OK, shorten your rounds to that length (no other), and fire them.

Greg
 
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Halfnutz said:
www.midwayusa.com

Winchester Match Ammo 308 Winchester 155.5 Grain Berger FullBore

Winchester Match ammunition is loaded with the highest quality components under the strictest tolerances to produce consistent, accurate ammunition for...
www.midwayusa.com www.midwayusa.com

Guessing this is the stuff.
Click to expand...
If that's the ammo, then it's stated right in the product overview:
Note: To maximize the accuracy potential this cartridge is loaded beyond the overall length recommended in SAAMI for .308 Winchester cartridges. As a result, cartridges may not fit in all firearm magazines.

There's also several reviews, one of them 2 months old stating these rounds won't work in AR-10 magazines. Now if they didn't add the information about the overall length until the negative reviews came in, they should work with you for refunding or exchanging with something that will work in your rifle.
 
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Badshot308 said:
If that's the ammo, then it's stated right in the product overview:
Note: To maximize the accuracy potential this cartridge is loaded beyond the overall length recommended in SAAMI for .308 Winchester cartridges. As a result, cartridges may not fit in all firearm magazines.

There's also several reviews, one of them 2 months old stating these rounds won't work in AR-10 magazines. Now if they didn't add the information about the overall length until the negative reviews came in, they should work with you for refunding or exchanging with something that will work in your rifle.
Click to expand...

Not much comparable in stock to exchange it with. I thought they didn't take returns on ammo either.

"Due to safety considerations and legal/regulatory reasons, Ammunition may not be returned." - MidwayUSA
 
Badshot308 said:
If that's the ammo, then it's stated right in the product overview:
Note: To maximize the accuracy potential this cartridge is loaded beyond the overall length recommended in SAAMI for .308 Winchester cartridges. As a result, cartridges may not fit in all firearm magazines.

There's also several reviews, one of them 2 months old stating these rounds won't work in AR-10 magazines. Now if they didn't add the information about the overall length until the negative reviews came in, they should work with you for refunding or exchanging with something that will work in your rifle.
Click to expand...
Literally none of that was there when I ordered it a few months ago. I had it shipped to mainland family I was visiting and then flew back home with it within the last week which is why I’m only discovering the problem now.
 
Badshot308 said:
All you can do at this point is to contact Midway and see what they say. They do have this is stock which would be ideal for your purpose. https://www.midwayusa.com/product/1020688022?pid=573027
Click to expand...
Appreciate the suggestion man. They don’t ship here and I ideally need ~200 identical rounds to work data, so I’ll just have to keep looking or potentially follow the smart advice of the reloaders that offered their knowledge up in this thread.
 
Submarine Sharpshooter said:
Appreciate the suggestion man. They don’t ship here and I ideally need ~200 identical rounds to work data, so I’ll just have to keep looking or potentially follow the smart advice of the reloaders that offered their knowledge up in this thread.
Click to expand...
If they ship it to your family on the mainland, can your family then legally ship it to Oahu?
 
@Submarine Sharpshooter.

Berger manual states 2.810 for COAL for 155.5gr.
The only Win powder they list is W748 with a MAX load of 45.8gr.

I really dont think seating them to mag length will case you an issue in regards to pressure. But in an abundance of caution I would seat them incrementally as I said above.

I see Winchester does not even list that ammunition as available on thier website. Berger however does have a factory 155.5 loading.

Hope this helps, and good luck. Let us know how it works out.
 
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If they won't take them back, exchange, or ship to Hawaii I'd just seat them to magazine-length and shoot them.

The Bergers are superior bullets. 748 is OK. As I suspected, those are for Palma and single-shot bolt action competitors.

What small-frame rifle are they for, and what is your barrel length and twist? 155s do their best at range when driven fast out of 28- to 30-inch bolt rifles doing around 2850-2900 fps at the muzzle.

Shorter-barreled gas-operated guns do just OK, but the bullets will start out slower and velocity decay starts as they un-cork.
 
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Submarine Sharpshooter said:
It’s Winchester loaded with 155.5gr Bergers. It is 100% factory ammo purchased directly from Midway USA. I thought it looked a little out of spec / long when it arrived (visiting family in mainland because midway doesn’t ship to Oahu).

Within the last week Midway has added a banner - way at the bottom - warning of being loaded outside SAAMI standard. I’m strongly considering contacting their CS and trying to get my money back, as buying five hundred dollars of factory ammo that turns into a handloading project right out of the gate is unsat. Right now I believe plan A is to sell it to fund new ammo and that plan B is Mexican match.




We’re thinking the same thing with respect to the last line, I have KAC M110 mags that get you to 2.875ish, as opposed to the commercial standard of 2.8 you get with most AR10 mags

also, thank you to everybody that dropped in for your input - sincerely, it is appreciated
Click to expand...

I have Knights Armament mags and they will not accept 2.875” rounds, 2.850” yes but not much longer.
 
Midway, or any other vendor is likely not to allow a return. If they don't, I would just take a few and seat them to fit your magazine and fire a few of them. Take the fired cases and check for any primer pocket stretch.

I don't believe you're going to get into any issues with a 155 seated in a bit deeper.
 
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Thanks all for the input, I very much mean that.

I’ll be doing surgery on them at some point in the near term most likely, because the primers are obviously quite rare - and follow all the sound advice that was given here.

For a more immediate solution, my LGS helped me out with ten boxes / 200 rounds of Nosler this morning - stoked.
 

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Halfnutz said:
@Submarine Sharpshooter.

Berger manual states 2.810 for COAL for 155.5gr.
The only Win powder they list is W748 with a MAX load of 45.8gr.

I really dont think seating them to mag length will case you an issue in regards to pressure. But in an abundance of caution I would seat them incrementally as I said above.

I see Winchester does not even list that ammunition as available on thier website. Berger however does have a factory 155.5 loading.

Hope this helps, and good luck. Let us know how it works out.
Click to expand...
I found some factory Nosler this morning that will work, but I’ll be doing some surgery on these rounds (following all the sound steps laid out here) to rehabilitate these at some point soon. I was going to drop some scenars that I have in, but if these are considered highly superior bullets then I will probably just see how these do.
sinister said:
The Bergers are superior bullets. 748 is OK. As I suspected, those are for Palma and single-shot bolt action competitors.

What small-frame rifle are they for, and what is your barrel length and twist? 155s do their best at range when driven fast out of 28- to 30-inch bolt rifles doing around 2850-2900 fps at the muzzle.

Shorter-barreled gas-operated guns do just OK, but the bullets will start out slower and velocity decay starts as they un-cork.
Click to expand...
It’s a 1:10 twist on an 18 inch craddock all bolted up to an F4 SF-10.

And I don’t disagree, but I’m fine with the shorter exposure time and the associated shorter top end effective range that goes with it - some context, I also have a .300 Winnie that is an outstanding rifle with fully developed loads (I did so many in 2012 that I’m still using that exact same batch today) - so the lighter rounds in the .308 won’t exactly be limiting, just creating a clear distinction between which of my hunting rifles is a <500m gun and which is a >500m gun.

If I feel like the terrain is going to place a premium on longer shots, I’ll just stick that in the rifle scabbard instead. Side note, I realize the .300 Winnie is superior in all situations, but the comfort / security I derive from being behind an AR15 after living with an M4 and Mk18 really can’t be beat to me. I may always prefer a gas gun for the reason of “just because I do” so long as the situation affords for it to be a legitimate option.

And really, again, I’m thankful for all the awesome input from everybody and am impressed with what a great community SH is
 
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Submarine Sharpshooter said:
It’s a 1:10 twist on an 18 inch craddock all bolted up to an F4 SF-10.
Click to expand...
Seat them back to 2.810 - 2.830 and you've basically got 7.62 Ball with a good target bullet. Should work right through your Craddock and can.

Probably a little light for elk (although I used a 155 Lapua Scenar on the last elk cow I shot). Mule deer. Maybe antelope.
 
Ironically, I have a few boxes of 155 scenars and considered experimenting with them on both my .308 and .300 Winnie. I’ve yet to use them on anything, just a bullet I’ve always been curious about. I feel like with the .300 win in particular I could get some very flat shooting and short exposure times out as far as 800m.

I feel like they might end up a little over spun in a 1:10 / 24 in .300 win but they are pretty long relative to other 155s, but the bottom line is that I’ve got what I need to work a .300 win mag 155 scenar load. Crazy to you or seem plausibly effective, Sinister?
 
I so thought this thread was gonna be about cutting Xs in some soft point bullets for better expansion. Boy am I disappointed
 
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Submarine Sharpshooter said:
I feel like with the .300 win in particular I could get some very flat shooting and short exposure times out as far as 800m.

I feel like they might end up a little over spun in a 1:10 / 24 in .300 win but they are pretty long relative to other 155s, but the bottom line is that I’ve got what I need to work a .300 win mag 155 scenar load. Crazy to you or seem plausibly effective, Sinister?
Click to expand...
The Scenar is a tiny bit longer than a 175 MatchKing, about the same as a 165 Ballistic Tip. The front quarter is airspace under the ogive. If it holds together it should be a pretty wicked 800-yard (maybe better) load.

1617841638307.png
 
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Not to sound like a dick but I honestly believe you should put the tools down and read up on some very basic metrics that may save your life, your eyesight and or your hearing and body parts.

Getting on the internet and polling people for YOUR answer is not a great way to start.
When I say "Your" I mean one that you want to hear.
 
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On longerangehunting.com a couple of guys are pushing the Lapua 155 Scenar to 3285 fps out of 300 Winchester Short Mags.

Seems consensus is the Scenar is a thicker jacket than the Berger hunting bullet.
 
Ravenworks said:
Not to sound like a dick but I honestly believe you should put the tools down and read up on some very basic metrics that may save your life, your eyesight and or your hearing and body parts.

Getting on the internet and polling people for YOUR answer is not a great way to start.
When I say "Your" I mean one that you want to hear.
Click to expand...
It’s fairly pretentious and rude to assume that I’m not in possession of those very basic metrics simply because I also wanted to solicit for experiences / inputs from other humans such that those could, if they were valuable, help inform my decision.

And then talk down to me for it. For example, I’m a very effective spearfisherman and freediver. Despite that, how often do you think I talk to other solid people in that niche? All the time, and everytime I do I’m looking for something they do better than me or something I don’t know such that I can put in my toolkit.
 
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sinister said:
On longerangehunting.com a couple of guys are pushing the Lapua 155 Scenar to 3285 fps out of 300 Winchester Short Mags.

Seems consensus is the Scenar is a thicker jacket than the Berger hunting bullet.
Click to expand...
I’m pretty interested to try it. I think you know where I’m going - light / high MV but with the BC of what is usually a heavier round - could be a killer combo.

I think I’ll side by side them with my 195s next time I hit the range.
 
Submarine Sharpshooter said:
It’s fairly pretentious and rude to assume that I’m not in possession of those very basic metrics simply because I also wanted to solicit for experiences / inputs from other humans such that those could, if they were valuable, help inform my decision.

And then talk down to me for it. For example, I’m a very effective spearfisherman and freediver. Despite that, how often do you think I talk to other solid people in that niche? All the time, and everytime I do I’m looking for something they do better than me or something I don’t know such that I can put in my toolkit.
Click to expand...
Well said.
 
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