Seating boolet below the neck????

[lotech]

I own no benchrest rifles, but have gotten 100 yard groups with factory guns in the 3/4"-1" range consistently using #314299 cast of ww alloy in at least a couple of .308s. Not award winning groups, but good for me. This bullet must be seated below the case neck in the .308. Leading hasn't been a problem.

I'm sure there are exceptions and the NRA project may have dealt with such. I don't specifically recall the article but I'm sure I've read it at least once. I have referred to the book often over many years, but have not looked at it recently. I don't recall anything specific at the moment, but haven't some of E.H Harrison's cast bullet theories been disproven in recent times?

[Larry Gibson]

If a "theory's " results are producible then it is no longer a "theory". Years ago when I recovered a lot of my own cast bullets out of a .308W rifle that had been impacted in snow I noticed that many the 311284s which were seated below the case neck had gas cutting damage similar to the picture. The 311299s I fired did not. It's why I don't seat below the case neck (top of the GC anyway).

As I mentioned previously there are other variables. One is the seated depth below the case neck. There is no right or wrong answer here. If seating below the case neck suits one's purposes then doing so is fine as long as a crimped on GC is used so no safety problem arises. Some of us just prefer not to seat cast below the case neck for proven reasons.

"I own no benchrest rifles, but have gotten 100 yard groups with factory guns in the 3/4"-1" range consistently"

Impressive, you should enter CBA matches. You would win many of them.

[lotech]

I don't think I would win often. I've never been fortunate to own an "all day long" rifle and I certainly don't shoot a good group everytime. Perhaps "consistent" was a poor word choice, but I didn't expect the acerbic response. Like many others, I can manage enough good groups to know I have an accurate rifle and a good load.

[Larry Gibson]

"Acerbic response".......?

You asked the question about Harrison 's theories being disproven. I answered honestly that if proven and reproducible it is no longer theory but fact.

I also congradulated you on your own claimed ability and suggested you to compete in CBA matches.

How is either "acerbic"?

Since there is no yes or no answer the discussion may provide insight for others. All that was intended was a further discussion of the OPs question.

[robg]

I've tried both ways in my 308 with 180 gr boolits .I got better accuracy with the check in the neck.but I don't think its set in Stone probably just me.

[ShooterAZ]

Sometimes we have to do it. I certainly don't recommend it, but in the 300 Savage it is below the neck, same with 300 Win Mag. Sorry since I since I got my new computer...my photos are all messed up and I'm struggling with attachments. It won't load right.

[Oklahoma Rebel]

exactly how "tall" is a gas check? (I mean the sides)

[Boolit_Head]

exactly how "tall" is a gas check? (I mean the sides)

Tall enough? I have seen gas checks of different heights but most were similar.

[Oklahoma Rebel]

wow, that was loaded with useful info!

[Boolit_Head]

Glad to be of help!

[Oklahoma Rebel]

love the avatar by the way, it tops em' all!

[Bama]

After looking at a foriegn military study, per study it only requires one bullet diameter to form as good a gas seal as possible with the paticular boolit. Based on that, extending bullet farther into the case than required will not help seal or improve accuracy so why do it if not required for throat fit. Also it takes up case capacity which has to be monitored carefully to control pressure on higher velocity loads.

[Boolit_Head]

With some cartriges there is not much choice. Take the 300 blackout, heavy bullets running subsonic with a short case neck is a recipe for seating deep into the case.

[Bama]

Seating a gas check below the neck with a near max load is also a concern with reduced case capacity. This is one reason I started sizing bore riders to fit inside the bore so they can be loaded with the gas check fully inside the neck. It gives good bullet alignment and improves my accuracy.

[MT Chambers]

The .308 and .30 br. require most accurate boolits to be seated below the neck, my most accurate loads in those two cals all have the Gc well below the neck. the pressure of ignition will keep the check on till it's out the barrel (prolly talking 40,000 psi).

[Tom Myers]

exactly how "tall" is a gas check? (I mean the sides)

The Precision Load Records ~ 5 software contains a gas check database containing a complete dimension chart for both Hornady and Gator gas checks.

Hope this helps;

[Larry Gibson]

Seating the GC below the case neck is not always detrimental to accuracy. Thus there is no clear cut yes or no answer on this question.

There are sufficient bullet designs available that keep the GC in the neck of the shorter neck cases. In the .308W for instance I've found a lot of different designs that keep the GC inside the neck. With the 311299s I've used over the years at least the top of the GC is kept within the neck, even on a couple very short throated ones. As with Bama I also will size the bore riding noses when necessary so they "fit" the bore so the GC doesn't have to be seated deep. This has proven beneficial especially when pushing the cast bullets to high velocity with psi's of 35,000 to 50,000 psi.

[blackthorn]

And, to state the obvious, here is another reason to make a chamber cast. It will tell you what the absolute maximum length your case length can be and still remain safe from binding.

[Rcmaveric]

I was sketchy about loading gas checks below the case neck. Tried because of no other choice. Didn't really affect accuracy.