Hesse receiver deminsions

[hsp223]

I have just gotten a Hesse from the group buy and have noticed some deminsional irregularities. Most are easily fixed with a file and/or Dremel tool. However, I need to know the distance between the front of the receiver face and the surface that the bolt carrier abuts to from other Hesse receivers THAT HEADSPACE properly. The reason is that I can return the receiver for replacement but I cannot alter the receiver in any fashion. It is hard to judge what it will headspace at without doing some modifications and putting on parts. So if I can compare the measurments of the reveiver bridge thickness of other functional Hesse's then I should get an idea of where mine sits with regard to headspace. Mine is a bit short when compared to an Imbel. It also looks like I may have a Gary Jeter special as far as timing is concerned. Hand tight barrel to 10:30 and it abuts to inner shoulder and outer shoulder at same time. To get it to time properly I would have to set the barrel closer to the locking shoulder by grinding on both surfaces (inner shoulder of receiver and shoulder on barrel). I don't want headspace to be too short. In another thread someone had determined their locking shoulder size to be .203 (something is amiss) in a Hesse receiver.

In all fairness to Robert Hesse, he will take the receiver back, inspect it and replace it if nessecary. But I don't want to send it back. I like the looks of it (it's a little beefier than the Imbels). Most importantly I want the challenge of whipping this thing into shape. The more problems the better (to a point). I think a series with pictures and progress and what to look out for would be beneficial to those who decide to build on a Hesse.

[W.E.G.]

I doubt that I'm qualified to comment on this. But, what the heck. It never stopped me before!

I presume that, without actually installing the barrel, you are trying to determine whether the receiver is capable of headspacing correctly.

What good is it to know the distance between the forward-most face of the receiver and the point of impingement between the bolt <u>carrier</u>?

The bolt drops-down into engagement with the locking shoulder well before the carrier reaching its most forward position.

Since you have detected impingement between the secondary receiver face and the breech-face of the barrel, I presume you are thinking about relieving the breech-face of the barrel rather than relieving the secondary face of the receiver. I further presume that you fear that doing so may may result in short headspace once the barrel is indexed to TDC on what may be an out-of-spec receiver.


I HAVE A SUGGESTION

"The WECSOG Wax-Pellet Headspace Test"

1. Hand-tighten the barrel to wherever it stops.

2. Calculate as best you can, how many degrees off TDC you are. You said 10:30, so thats about 45 degrees. If you are exactly 45 degrees off TDC, then tightening-down the barrel to TDC will take up 0.007812" slack in the headspace. Explanation follows.

3. Multiply the number of degrees short of TDC you are by a constant of 0.00017 inches. Make a note of that number, as it is the the value you will subtract from the hand-tight headspace measurement measurement to be obtained in Step 13.
(In case anybody is checking my math...Uncle Buck?..., here goes:
The thread pitch of the barrel is 16 TPI.
There are 360 degrees in a revolution.
One revolution of the barrel changes headspace 0.0625 inches.
0.0625 inches divided by 360 degrees equals 0.0001736 inches change in headspace per degree of barrel rotation.
Sombody slap me if I got this wrong.)

4. Insert a pin gage of reasonable dimension in the locking shoulder recess. I suggest something in the range of 0.258" to 0.262".

5. Insert a "go" gage (1.630") in the clean chamber of the hand-tight barrel.

6. Obtain a ball of stiff wax about the size of a BB, perhaps a bit larger. The idea is that you are going to mash it into a wafer between the boltface and the headspace gage. You don't want it oozing out beyond the boltface. But neither do you want just a mere fleck.

7. Coat the ass-end of the headspace gage, and the face of the <u>stripped</u> bolt with some sort of release agent...like oil.

8. Slide your stripped bolt/carrier assembly into the receiver rails, and push it forward to the vicinity of the breech face.

9. Using three hands or however many toes, place the wax ball between the face of the bolt and the ass-end of the headspace gage.

10. Gently push the bolt/carrier assembly forward so as to compress the wax ball between the gage and the bolt face, and allowing the carrier to move into the full-forward position. The bolt should drop "into battery" during this operation.

11. Gently retract the bolt/carrier assembly, and retrieve the compressed wax ball.

12. Measure the thickness of the wax ball. (Yes, I know wax is elastic, and this measurement will not be an absolute measurement of the space between the gage and the bolt. But, its close enough for WECSOG.)

13. Now, calculate the sum of 1.630 and the thickness of the compressed wax ball. Hopefully the number will be something close to 1.640"

14. Next, subtract the value you obtained in Step 2 from the value obtained in Step 13. Voila! This number is what your headspace would be if you could tighten-down that perfectly good barrel on that P.O.S.-Hesse receiver.

Everybody agree?

[stimpsonjcat]

Wow Gary...you burned some brain matter on that plan!

If you're not satisfied after trying Gary's calcs...you might want to send it back...just cause gary had to suffer thru this is no reason for you to do so.

I wonder what Mr. Hesse does with these receivers that are totally whacked out when he gets them back? Pitch em...or send em to the next guy?

What's the serial #? (don't post here) past a certain # they were suppossed to be fixed right?

Here come the Hesse builds Gary!

EDIT------------------------

Ooooooooooooooo did you notice that hsp223's FALoholic # is 667? The neighbor of the beast!

[ August 29, 2001: Message edited by: stimpsonjcat ]

EVEN MORE EDITS------------------

I wonder if there is a Hesse receiver #666...anyone? There's just something about that idea that makes me grin...>:}

[ August 29, 2001: Message edited by: stimpsonjcat ]

[W.E.G.]

"Oh the stories we'll tell!"

[idsubgun]

Wasn't the serial number supposed to be above 10,000? I think I remember that number from somewhere.


EDIT: I just did a search and the number was 4000. Whew, mine is in the 9000 range.

[ August 29, 2001: Message edited by: idsubgun ]

[hsp223]

isubgun- mine is in the 9000 range as well, and I have noticed a few more Hesse threads of late. Me thinks Gary's prediction concerning the Hesse group buy is comming true. A brand new class at WECSOG U.

Gary-I have already done something similar to what you have suggested and have determined that my headspace should be within reason, I just didn't know how to explain it within a reasonable amount of text. My method was half as involved as yours but it would have taken me 2 or 3 times more text to explain it as well as you did. Breifly, I hand tighten the barrel and figured I needed about .008 to get to TDC. I then put in the NO GO and striped bolt and measured headspace with pin guages. It fell in the middle around .262 after adding the .008 or so. It seemed that the bolt made contact with the guage, now I am wondering if it really did. I didn't use any wax between the bolt and guage. I will recheck tonight. I did notice that the bolt carrier would not go completely forward (unless assisted with a hammer) and make contact with the front inner surface even though the bolt was seated. I beleive this is caused by the differences in depth (between the front edge of the receiver and the inner surface that the carrier abuts to) between the Hesse and Imbel reveivers. This is what worries me. It is unsightly (1/8 inch gap). Even though it may have no consequence as to safety, I am sure I will think the bolt is out of battery when I see this gap. Since I have an Imbel and some receiver stubs to compare to, I will try to post the differences in measurements.

[hsp223]

HOLD ON! THAT 1/8 INCH GAP IS HAZZARDOUS AND UNSAFE! I rechecked my deminsions last night and discovered some suprising things. The depth between the front surface of the receiver and the inner surface that the bolt carrier abuts to is 0.985 in the Imbel (new) and 0.928 in the Hesse. A difference of .057. I believed this is where my problem was. I had some barrel stubs sitting around and decided to measure them. They measured in at .965, .958 and .958, which is in the middle of my Imbel and Hesse. This may not be the problem after all. Further inspection revealed a gap (1/16 inch) between the bolt and go guage when the carrier was used. This is the situation that leaves a 1/8 inch gap between the bolt carrier and the inner surface of the receiver that it abuts to. Gary Jeter was right to put a ball of wax between the bolt and go guage. I didn't and this could have led to a disasterous result. It means that the bolt doesn't close on a round in the chamber and if by some means the firing pin hits the round, I could have an out of battery detonation.

It turns out that the upper forward edge of the bolt is making contact with the top of the receiver holding the bolt back about 1/8 inch. This only happens when a guage or a round is in the chamber. If no round is in the chamber then there is room for the bolt to slip under this edge. A little filing on this surface before barreling should fix the problem.