Headspace question , need advice

[problemchild]

I dont have the exact bushing I need for 223. I do have another bushing made for measuring ogive. That bushing sits .02 higher on the shoulder than the "correct" bushing. I used factor new FGMM 223 to give me a reading of 1.496 on new unfired ammo. Can I use that measurement to resize my brass as long as its in the same spot of the shoulder?

I am supposed to use bushing b 350 and I do not have that bushing. Its a large bushing like the d 400 used for the 308 in the picture.

[popeye4]

If you're going to buy a bushing, get the Sinclair bushings. They are steel (not aluminum) and are cut to the shape of the shoulder.

When you say "higher on the shoulder" do you mean closer to the mouth? Or do you mean the "ogive" bushing is 0.352" while the shoulder bushing is 0.350"? I think you will be fine using the bushing at hand for the time being, as this is a somewhat relative measurement when setting the resizing die. Using a datum point a couple thou off shouldn't affect the results. If new brass is all you have to go by, you'll at least size your fired brass to be the same as unfired Federal. As to whether that's the appropriate size for your gun, I cannot say. Make sure you keep good notes, as you don't want to start confusing bushing A with bushing B cases.......

BTW, I have a "go" gauge I use to set my shoulder to when loading for my AR. I also use the Redding Instant Indicator and it comes with a "go" gauge to set the zero on the dial indicator.

[FLIGHT762]

For the .223 Remington, the Hornady A-.330" bushing is the proper bushing to use, not the B-.350"

http://www.hornady.com/assets/files/catalog/2009/69-70_precision_gauges.pdf

[problemchild]

Thanks

I cannot find the sinclair bushings. Only hornady.

I see the other post that corrects the bushing I need as well. Thanks for that.

Ill give this a go tomorrow when Im rested and order the correct parts Monday.

If you can link to the sinclair steel bushings I would be grateful.

If you're going to buy a bushing, get the Sinclair bushings. They are steel (not aluminum) and are cut to the shape of the shoulder.

When you say "higher on the shoulder" do you mean closer to the mouth? Or do you mean the "ogive" bushing is 0.352" while the shoulder bushing is 0.350"? I think you will be fine using the bushing at hand for the time being, as this is a somewhat relative measurement when setting the resizing die. Using a datum point a couple thou off shouldn't affect the results. If new brass is all you have to go by, you'll at least size your fired brass to be the same as unfired Federal. As to whether that's the appropriate size for your gun, I cannot say. Make sure you keep good notes, as you don't want to start confusing bushing A with bushing B cases.......

BTW, I have a "go" gauge I use to set my shoulder to when loading for my AR. I also use the Redding Instant Indicator and it comes with a "go" gauge to set the zero on the dial indicator.

[FLIGHT762]

Sinclair part # 09-10230, $9.95. Your Hornady bump gauge/ comparator holder works with the Sinclair gauges. No need to buy the Sinclair gauge holder.

http://www.sinclairintl.com/.aspx/pid=35265/Product/Sinclair_Bump_Gage_Insert

[rsrocket1]

Your method will work so long as you stay consistent with what you measure versus what you really want.

Why?
The headspace measurement assumes the same shoulder angle between your particular gun and the industry standard. If they weren't, headspacing halfway up the shoulder is useless. You'd need an exact measurement of your gun's chamber and duplicate it with a full shoulder headspace gauge.

Try this:
Get a fired case from your gun and color the shoulder with a magic marker. If you don't have a fired case, full length resize and shoot in your gun.
Chamber it and close the bolt. Look for any spots where the marker rubbed off. If there was none, use that case. If there is some rub off, bump the shoulder back 1/12th turn at a time with a full length die, remark, rechamber. Repeat until there is no rub off.

Measure the headspace with your particular set up. Now you know that with your die, you can set the headspace in your gun with that measurement.

This is for a bolt action gun, right? Of course if it's for an autoloader, don't bother, just full length resize every time.

[problemchild]

Sinclair part # 09-10230, $9.95. Your Hornady bump gauge/ comparator holder works with the Sinclair gauges. No need to buy the Sinclair gauge holder.

http://www.sinclairintl.com/.aspx/pi...mp_Gage_Insert

Thanks. I ordered the parts.

[problemchild]

Sinclair part # 09-10230, $9.95. Your Hornady bump gauge/ comparator holder works with the Sinclair gauges. No need to buy the Sinclair gauge holder.

http://www.sinclairintl.com/.aspx/pi...mp_Gage_Insert

Got the new sinclair gauges. Very nice and thanks for the link.

[huckberry668]

you don't need a 'correct' bushing just need to use the same one for all measurements. as long as the diameter is larger than the neck and smaller than the bottom of shoulder. I think I use the .30 cal bushing for my 223 brass.

[problemchild]

you don't need a 'correct' bushing just need to use the same one for all measurements. as long as the diameter is larger than the neck and smaller than the bottom of shoulder. I think I use the .30 cal bushing for my 223 brass.

The sinclair bushings measure the entire shoulder and have an angle cut. Normal bushings have only a sharp datum line contact patch which leads to the measurement shifting all over as you twist the bushing.

[huckberry668]

The sinclair bushings measure the entire shoulder and have an angle cut. Normal bushings have only a sharp datum line contact patch which leads to the measurement shifting all over as you twist the bushing.

shifting all over... Mine works fine for me for over 20 years. It just takes some practice. I take several measurements to get a consistent reading. Nowadays I get it right the first time but still do it a few more times to be sure. The Sinclair tool does sound great though.

[popeye4]

shifting all over... Mine works fine for me for over 20 years. It just takes some practice. I take several measurements to get a consistent reading. Nowadays I get it right the first time but still do it a few more times to be sure. The Sinclair tool does sound great though.

The problem I've had with the aluminum Hornady bushings is that the sharp contact edge rounds over time, changing the reading. I can sharpen it up with a little touch-up grind, but it still is a variable over time. The Sinclair gauges are not susceptible to this type of variation. Since I'm trying to be consistent from batch to batch, changing the reference point over time is unacceptable.