Headspace Head Scratcher

[Jeffersonian]

Are you able to measure the velocity of those two loads? My initial guess would be the velocity is enough different that it works well with one load and not with the other. The reason this could happen is if one of the cases has to be 'blown out' to fit the chamber the velocity will be lower since some of the energy is being used to fire form.

I would love to, but unfortunately I do not yet have a chronograph.

 

[Jeffersonian]

My first question is why are you neck sizing?….
Second thought would be the m1 ammo most likely has a roll crimp which would tell me your Winchester likes more neck tension, this is backed up by the fact you say factory ammo shoots well which definitely has a lot of neck tension,… just my initial thoughts .
Wayne

I was (probably not anymore) neck sizing on the premise that neck sizing enhances accuracy.

I guess that myth is busted at least in my case

 

[DShortt]

The only rifle I've had thus far that benefited for neck sizing turned out to be a different situation altogether. It was early on in my reloading career and I was adjusting the FLS die according to the manufacturer's instructions. I found much better accuracy the second loading using a neck size die. Later on I discovered that the FLS die when adjusted to the manufacturer's instructions was actually sizing the brass too much for that particular chamber. I changed my die setting on the FLS die and had no more problems.

I experimented with neck sizing on other barrels and could not tell any difference on the target so I no longer do that with anything.

Just my personal experience.

 

[bozo699]

I was (probably not anymore) neck sizing on the premise that neck sizing enhances accuracy.

I guess that myth is busted at least in my case

For a hunting rifle I would never neck size actually with the exception of a 22 hornet I can’t think of any good reason to ever neck size only. I think if you bump your shoulders maybe .002 and increase your neck tension your groups will tighten up.
Wayne

P.S if your going to reload you need a chronograph, there people on here that say you don’t but you will actually use less components working up a good load with one and wayyyy less components building your dope charts!…

 

[K22]

I was (probably not anymore) neck sizing on the premise that neck sizing enhances accuracy.

I guess that myth is busted at least in my case

It was "busted" decades ago - but many of us believed it the 60's and 70's, I have a drawer full of neck sizing dies to prove that I was one of those poor souls duped by this myth promulgated by gun magazine writers. Now the internet has replaced the writers with more wild tales and ideas.

Even worse, was the "partial sizing" idea promoted using a F/L die. That created extruded cases, bulges in the neck area, concentricity problems. Fortunately, I never fell for that one.

 

[BoydAllen]

In the past I have used Lee Collet dies for varmint loads that were not hot. I could get several loadings that way without issues, and the accuracy was quite acceptable. When I wanted to knock out 80 varmint loads, no having to lube or remove lube saved a lot of time, and with no shoulder bump or body diameter sizing case growth was just about nonexistent. Combine this with using a suitable ball powder to throw charges directly into cases and the whole procedure became significantly more convenient. If we shift gears to a pure paper punching situation, where I want the absolute smallest group I can get, I FL size (bushing) , or combine a LCD with a properly set body die. What I do not want, even for live varmints is loads that give me a mixture of tight and easy bolt close.

 

[BoydAllen]

In the past I have used Lee Collet dies for varmint loads that were not hot. I could get several loadings that way without issues, and the accuracy was quite acceptable. When I wanted to knock out 80 varmint loads, no having to lube or remove lube saved a lot of time, and with no shoulder bump or body diameter sizing case growth was just about nonexistent. Combine this with using a suitable ball powder to throw charges directly into cases and the whole procedure became significantly more convenient. If we shift gears to a pure paper punching situation, where I want the absolute smallest group I can get, I FL size (bushing) , or combine a LCD with a properly set body die. What I do not want, even for live varmints is loads that give me a mixture of tight and easy bolt close.

 

[searcher]

I was (probably not anymore) neck sizing on the premise that neck sizing enhances accuracy.

I guess that myth is busted at least in my case

I'll go contrary to others on this opinion. There is nothing wrong with neck sizing hunting ammo. If headspace is correct and neck tension adequate to securely hold the round in place when recoiling in a magazine, etc., it provides the same benefits in accuracy as it would in a target rifle. I shoot neck sized (with turned necks) in my 7 MM Remington Mags (semi-auto, no less) and other higher-recoiling rifles with no problems. If not enough tension is used, however, the bullets can move in the cases and throw accuracy all over the place, not to mention dumping powder in your action if one of these rounds is ejected from the chamber unfired and the bullet decides to stay in your throat - as they can move out of the case enough to stick in the lands, though normally, they become seated deeper in the case. Those problems are only encountered if someone is not paying attention to what they are doing when loading or are not willing to do a little trial and error in applying the proper neck tension when setting up their load. My guess is there are just as many inaccurate rounds being fired from over-crimped or improperly crimped rounds.

 

[swd]

I was (probably not anymore) neck sizing on the premise that neck sizing enhances accuracy.

I guess that myth is busted at least in my case

No one that shoots competitively neck sizes only. Benchrest and F Class rifles all FL size. If neck sizing was more accurate we’d all be doing it and those are the most accurate shooting disciplines.