Excess headspace causes poor accuracy?

[earlmck]

Got my latest "Handloader" magazine yesterday. A fellow with an old Winny 30/30 he'd inherited had a question about "funny-looking empties and poor accuracy despite a nice bore" for Brian Pearce (who I respect as a gun guy and author). Brian correctly diagnosed the brass as showing badly excess headspace and allowed as how it really wouldn't be worth paying a gunsmith to fix the problem on a well-worn antique (likely also a good assessment).

Then he surprised me. He told the fellow the lousy accuracy was a result of the excess headspace. I don't have a lot of experience with excess headspace, but both rifles that I am acquainted with having the problem didn't show any accuracy problems -- just real lousy brass life. What say you fellers? Does excess headspace actually cause the poor accuracy in a rifle? I'm thinking that fellow's old rifle has some other problem -- loose screws, barrel band fit, messed barrel crown -- something other than headspace.

And then Pearce told the fellow that there really isn't enough shoulder on the 30 wcf to do a "handloader fix" and headspace on the shoulder. Which I'm pretty sure is wrong -- I'd bet a Benjamin or two I could make brass that'd soak up the excess headspace via headspacing on the shoulder vs. the rim. You could use 38/55 brass but I'm guessing you could just use your 30/30 brass and probably only have to neck up to 32 or 8 mm (whatever is handy) and then size down until you barely close and -- voila!

I've never done a 30/30 that way but one of the rifles giving me my little bit of "excess headspace experience" is a "kid favorite" 25/20 from which I couldn't get 3 loads of brass life before head separation (serious pain) until I smartened up and began carefully making my 25/20's out of 32/20 and now I keep that brass separated and only neck size and haven't lost a case to head separation ever since.

So -- this same Brian Pearce, in addition to a little surprise in a leverguns answer, wrote a great article in the magazine on -- the "25/20 Winchester -- Improved Accuracy and Long-Range Performance"! Worth chasing down the mag if you are a 25/20 shooter. Although I suppose all us old 25/20 guys have long ago settled on our favorite load and are not a gonna' be doing much experimenting... Well, most of us old guys: I'm not so old yet that I won't occasionally experiment a little with new loads. Especially with my other 25/20 that doesn't have excess headspace and that I use in the "quarter-bore" match at our monthly shoot.

[GunnyMack]

I didn't see the report on the 30-30, was too intrested in the 25-20 article!

Sometimes I think these gun 'experts' give some false info to dissuade people from trying to fix such a gun. I never given a thought to the accuracy of a head space problem gun as if it's excessive the next step would be set back or rebarrel. In setting back then accuracy will come into play. So poor accuracy again leads to forearm, crown and yes even shooting technique.
It would be an interesting test of a known head space case.

[OldWin]

I don't know, I've had a 38-55 and a 32WS with some head space that shot fine.
If it were me, I'd check for crown wear or damage first.
If thay was good, I'd swap the locking block, bolt, or both. That's how I've always fixed 94s with head space. If it has a good bore, I'd never give up on it.

[GunnyMack]

Good point Jay- probably chase excessive headspace easily enough with a locking bolt.

[JimT]

If you read articles on the subject you will find gunsmiths who believe headspace affects accuracy and those who don't. I have read tests where an accurate rifle was taken and using one lot of ammo, fired groups, recorded them, then the headspace was increased and groups fired and recorded. As the headspace grew, the groups expanded. The tight (within tolerances) headspace was the most accurate.

HOWEVER ... what was NOT taken into account was the fact that as headspace grows, it is possible the firing pin strike becomes lighter. Not hitting as hard, driving as deep. And lighter strikes absolutely do lower the velocity and possibly the accuracy. So it could be that the larger headspace and less accuracy was due to primer strike, not necessarily the increased headspace itself.

That is something that probably should be tested.

[High Desert Hunter]

Over size locking bolts are available,.005 and .010. Might not eliminate it completely, but combined with neck sizing I bet the primer protrusion goes away. I too read that and was surprised.

[AJMD429]

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I'm thinking it probably could affect accuracy, but not likely enough that my skillset would ever reveal it.

I've seen competitive shooters write all sorts of things "don't matter" - and show their own results to prove it. It does seem like 'consistency' matters though, no matter what the parameter is. The other thing most of the handloaders who shoot competitively DO say matters is concentricity, but I guess that's also a form of 'consistency'.

[JimT]

I've seen competitive shooters who sized the flash holes the same, turned the necks of the cases, weighed the cases and made sure each cartridge was a consistent temperature when they chambered it. Besides weighing each bullet and checking them for consistency.

[AJMD429]

I've seen competitive shooters who sized the flash holes the same, turned the necks of the cases, weighed the cases and made sure each cartridge was a consistent temperature when they chambered it. Besides weighing each bullet and checking them for consistency.

Me too, and when I shot my most accurately was with a Ruger M77 Varmint in 6mm Rem, and I weighed powder charges, inside-turned the necks, used all the same lot of brass, and trued the flash holes. I also used a micrometer seating die that assured concentricity. With that the gun would put ten holes in a dime-size group at 100 yards all day long. But one day a friend who'd never shot a centerfire rifle came to visit, and at the time the only centerfire rifle I had was that one, but I'd not loaded any ammo....since I normally used compressed charges of weighed 4831, I just poured a little salad-bowl full of powder, and dipped twenty cases in, filling them then spilling out until just at the neck/shoulder junction. I seated the bullets quickly since we were in a bit of a time crunch but he wanted to shoot 'a real gun'. I figured at least we wouldn't blow the gun up (I think a bunch of that powder actually burned after muzzle exit, based on the flash from the 24" barrel - perhaps that was the real 'metering' of the charge). Anyway, we took the gun back to the shooting bench, and shot off a bag, at a paper target out at 100 yards. I fired the first three shots, just to be sure that if the gun blew up or something weird, it wouldn't hurt my friend. Through the scope (20x) the group looked awfully good. Then he shot, and the group had a couple flyers but he finished the two shots in the magazine, then shot five more, and the overall group was about the size of a quarter, discounting one flyer. I commented about how I was surprised at the accuracy since I hadn't loaded them carefully. So I asked if he minded if I carefully shot the other ten just to see how well the batch did, and he was fine with that - The group was STILL dime-sized...!

Now I'm sure a better shot than me, perhaps with an even better gun, would be awfully disappointed at a 'dime-sized' ten-shot group off the bench like that, but I sure was satisfied.

I've seen several podcasters who at least portray themselves as expert marksmen and reloaders isolate different aspects of the reloading process and shoot groups to prove that a particular aspect really doesn't matter (i.e. weighed vs volumetric charges, even seating depth...!). So I don't know what to believe....other than I'm just not a good enough shot to tell the difference most of the time. The weak link for me is most often the optic - if I can't see it WELL, I can't hit it.

I did have one gun (breakopen "45 Colt/410") that would 'group' about 6 inches with either factory 45 Colt or careful handloads - at 25 yards...!!! I'm guessing the long jump to the rifling allowed the short fat bullets to be sideways prior to engaging the rifling, although it didn't do any better with 410 slugs. I traded that one in (and yes I did tell the guy it was terribly inaccurate but he just wanted it 'for snakes' ).

[JimT]

The weak link for me is most often the optic - if I can't see it WELL, I can't hit it.

YESSIR!! That's me anymore with any type of sight. It's one reason I like to shoot targets early of the morning. On the Range, the sun comes up directly behind me. I can see the target AND the sights clearly. When I can see it, I can hit it.

Your "dipping" the powder charge account goes along with what Richard Lee wrote years ago. He reloaded .30-06 for a test and weighed the charges carefully. Then he reloaded others and varied the powder charge by more than a few grains. Viewing his targets at 100 yards, you could not tell which was weighed and which wasn't.

In my .45 Linebaugh gun I did the same thing. Weighing carefully each charge in a batch of ammo and then using a dipper and loading a batch of ammo. The ones that I dipped the charges averaged out more accurate than the weighed ones.

I am sure there were other contributing factors. I shot the weighed ammo first. Perhaps I "settled" down and was more "steady" by the time I got to the dipped ammo. But it was fun doing.

[Scott Tschirhart]

I have read a few people who spent a great deal of time weighing charges, sorting brass and doing other things to try to get more consistency.

It’s probably all good up to a point. I have gotten to where I rely on my Dillon for most handloads and I don’t sort brass. I’m not sure I can tell any difference with most of what I shoot.

But I intend to be more intentional with a .22 Hornet that I have on order.

My question is about how that rifle developed excess headspace in the first place?

[Pisgah]

No disrespect to Mr. Pearce as I have enjoyed many of his writings, but... even the best simply run out of things to write sometimes... and the deadline looms, and baby needs a new pair of shoes.

Having read gun mags for 60 years now, I can assure the younger generation that EVERY subject, no matter how dumb, has been covered already, ad infinitum.

[Walt]

Just remember that in 1905 or thereabouts, it was proposed to close the US patent office because everything that would be invented, already had been.

[ywaltzucanrknrl]

Earl, I'm with you and I would try to fix the issue the same way you mentioned. Up to a point, headspace is not relevant if you brass is sized to the chamber. I would also agree the 30-30 has enough shoulder to make a difference, plus there is also grip between the cartridge and the chamber wall if the case is sized to the chamber, P.O. Ackley proved this point.

And if the cartridge is sized to the chamber, it will resolve the primer strike issue that was mentioned above.

I have several old rifles that have excessive head space for factory ammo, I solve the issue by handloading, generally by creating a false shoulder when I first fireform the cartridge and then after that by only neck sizing a portion of the neck.

[earlmck]

Earl, I'm with you and I would try to fix the issue the same way you mentioned. Up to a point, headspace is not relevant if you brass is sized to the chamber. I would also agree the 30-30 has enough shoulder to make a difference, plus there is also grip between the cartridge and the chamber wall if the case is sized to the chamber, P.O. Ackley proved this point.

And if the cartridge is sized to the chamber, it will resolve the primer strike issue that was mentioned above.

I have several old rifles that have excessive head space for factory ammo, I solve the issue by handloading, generally by creating a false shoulder when I first fireform the cartridge and then after that by only neck sizing a portion of the neck.

Perzactly. I don't know about you but I first tried to make the brass grow to fit the chamber by first -- "headspacing" on the bullet with bullet firmly wedged into rifling. Nope -- at 25/20 pressures the brass didn't grow enough. And second, by using a loop of string in front of the rim to make a force-fit. Again she wouldn't grow enough. The only thing that worked for me was what you call the "false shoulder" technique. That seems to work nicely.

[marlinman93]

Excess headspace can indeed cause accuracy issues, but it's not hard to deal with it and not have any gunsmithing done to the rifle also. Especially true for bottleneck cases like the .30-30 mentioned. If you full length size after every firing the excess headspace will be an issue all the time. But if you leave the cases as they were after first firing, and then only neck size them the shoulder will already be fire formed to the chamber. By only neck sizing brass and reloading it without full length sizing the brass is fire formed to that chamber, and will shoot great. It will also make case life many times longer by not working the brass after every firing.

[Walt]

What has always worked best for me is full length resizing but only to the point that I can feel a bit of resistance while closing the bolt. That's where I set my die.

[OldWin]

Loading your ammunition for the rifle in question is certainly the easiest "fix". The issue is when you have 12 rifles chambered for the same cartridge. I'm always concerned about "specially loaded cartridges". Probably isn't an issue with people more organized than myself.

[marlinman93]

Loading your ammunition for the rifle in question is certainly the easiest "fix". The issue is when you have 12 rifles chambered for the same cartridge. I'm always concerned about "specially loaded cartridges". Probably isn't an issue with people more organized than myself.

Since most of my old rifles have different groove diameters even in the same chamberings, I dedicate ammo specifically to what rifle it will be fired in. So when loading for some cartridges that I own a half dozen or more of, I usually use a slightly different bullet diameter, but almost always use the same charge and bullet weight or style. Some get sized differently, but if I happen to own 2 or 3 in the same grove diameter and cartridge then the box will be marked for all rifles it works well in.
I have four in .45-70, four in .40-65, six in .40-63 Ballard, five in .38-55 Ballard, three in .44-77SBN, and six in .32-40 Ballard. Maybe some others I have two or three of, but can't recall off hand.

[OldWin]

Loading your ammunition for the rifle in question is certainly the easiest "fix". The issue is when you have 12 rifles chambered for the same cartridge. I'm always concerned about "specially loaded cartridges". Probably isn't an issue with people more organized than myself.

Since most of my old rifles have different groove diameters even in the same chamberings, I dedicate ammo specifically to what rifle it will be fired in. So when loading for some cartridges that I own a half dozen or more of, I usually use a slightly different bullet diameter, but almost always use the same charge and bullet weight or style. Some get sized differently, but if I happen to own 2 or 3 in the same grove diameter and cartridge then the box will be marked for all rifles it works well in.
I have four in .45-70, four in .40-65, six in .40-63 Ballard, five in .38-55 Ballard, three in .44-77SBN, and six in .32-40 Ballard. Maybe some others I have two or three of, but can't recall off hand.

Im forced to do that with 44-40. All mine need something different. That's probably why I prefer 38-40. I can shoot the same load in all 7 of them. I only have one 32-40 now. I have 5 38-55s, but they are all Winchester 94s and will shoot the same load.
The hardest part is my dad has stuff too, so I kind of have to police that too these days. Still....old guns are way more fun no matter what we have to do.

[AJMD429]

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This guy is one of the ones who goes to the extremes in terms of reloading precision.

https://youtu.be/qkqOpLBjBe8

What he says (neck tension in this video) does make sense, and he gets target results that validate it, but for most of us we are not shooting with equipment, skills, or goals where the difference would be relevant.

Still fascinating to see technological boundaries pushed.

[marlinman93]

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This guy is one of the ones who goes to the extremes in terms of reloading precision.

https://youtu.be/qkqOpLBjBe8

What he says (neck tension in this video) does make sense, and he gets target results that validate it, but for most of us we are not shooting with equipment, skills, or goals where the difference would be relevant.

Still fascinating to see technological boundaries pushed.

Ammo I load to shoot a match is much more time consuming to build than what I shoot most times. I take a lot of time sorting brass, and making sure it's all the same brand, and perfectly matched. I've not found any reason to crimp at all for my single shot rifles nor has it shown any improvement in accuracy for those rifles. But for high power bolt action rifles in bottleneck cases a crimp does give better results.
I don't load any ammo for matches more than a month before shooting. I like to also cast the bullets for a match and lube them close to the time they'll be used also as lead hardens over time, and I wont shoot older bullets in match ammo that are cast lead. Numerous other things I do when assembling match ammo that seem to give better results, but take too much time for plinking or hunting ammo.

[Griff]

I put it in another thread, but... back when my eyesight was such that I could see target details and was able to shoot confidently, I did that anal bench rest accuracy reloading drill with my .30-30s for my target rifle. I had 100 rounds of Federal once fired cases from the same lot of ammo. I then sized, trimmed them to the same dimensions, weighed them after chamfering the mouths and uniforming the primer pockets & flash holes. Bullets were cast and segregated before sizing, then again after sizing/lubing/gas checking, segregated into target weight and everything else was just dumped into my ready to load bin. I ended up with 75 loaded rounds. They were only used for matches. Those empties stayed segregated from any other .30-30 rounds I might fire. I'm down to about 30 left of the original 75. I only get about 3 reloads from each piece of brass. Now, I really don't bother, I can't see the bullseye on the target @ 200 yards, so it's a by guess and by golly proposition if I can hit it. I have 6 rifles with scopes, an 1885 in .32-40, a 7mmRemMag Rem 700 BDL,its heavy barrelled mate with a synthetic stock, 2 ARs and a 375 Marlin. The heavy barrelled 7mm with the 10-25 powered scope can still shoot sub MOA groups with most any factory ammo, and with premium Nosler bullets does even better in my handloads. But, I have a lot more fun shooting the 1885 w/BP loads at 50 to 100 yards, or the 1885 low wall in 45 Colt @ 50 than I do with any of those other scoped rifles. I especially like to bang steel with the 30-30 out to 300 yards when I get that opportunity. I had more fun shooting at the 1538 yard Adobe Walls shoot in 2008 than a person should be allowed to have, even if I never hit one of the 3 targets! I "THINK" I have a tall enough staff on my tang sight to be able to get out that far now. I'm getting a new eye exam next week, maybe my new glasses with help me see that far!