7 replies to this topic

[TantumBull]

Okay, so let me start off by saying that what I'm about to ask has NEVER been brought up on these forums. Let me also say, that I didn't simply PM someone who's made this type of breech, because I wanted to here everyone's experience with it. Okay here goes...

There are two major brass breech types. I'm going to use 9/16 and 19/32 brass as examples here. The first type features the barrel, 9/16, housed in 19/32 that has a breech slot and a priming handle slot. The cocking handle is adhered to the 9/16. The 9/16 is pushed forward, a dart is placed into the slot in the 19/32, the 9/16 is pulled back, and the end of 19/32 is crimped inward so the dart is forced into the 9/16.

The second type is the one I have a question about. In this one, the 9/16 has a breech slot cut into it. A piece of 19/32 about an inch longer than the slot in the 9/16 is moved forward / backward (depending on how close to the gun the breech slot is located). A dart is placed through the slot in the barrel, and the breech cover is moved back. Here comes the question: When the dart is fired, it is still sitting in the half pipe, and is propelled forward. It suddenly has to go from a significantly wider area, to a significantly more tight area when the dart reaches the end of the breech slot. Does this downshift in tightness hinder the dart? It really seems like it would. Especially if the 9/16 had a tight fit on your darts.

Please answers from experience only. The point of this thread is to end my speculation, not to add to it.

[Split]

Okay, so let me start off by saying that what I'm about to ask has NEVER been brought up on these forums. Let me also say, that I didn't simply PM someone who's made this type of breech, because I wanted to here everyone's experience with it. Okay here goes...

There are two major brass breech types. I'm going to use 9/16 and 19/32 brass as examples here. The first type features the barrel, 9/16, housed in 19/32 that has a breech slot and a priming handle slot. The cocking handle is adhered to the 9/16. The 9/16 is pushed forward, a dart is placed into the slot in the 19/32, the 9/16 is pulled back, and the end of 19/32 is crimped inward so the dart is forced into the 9/16.

The second type is the one I have a question about. In this one, the 9/16 has a breech slot cut into it. A piece of 19/32 about an inch longer than the slot in the 9/16 is moved forward / backward (depending on how close to the gun the breech slot is located). A dart is placed through the slot in the barrel, and the breech cover is moved back. Here comes the question: When the dart is fired, it is still sitting in the half pipe, and is propelled forward. It suddenly has to go from a significantly wider area, to a significantly more tight area when the dart reaches the end of the breech slot. Does this downshift in tightness hinder the dart? It really seems like it would. Especially if the 9/16 had a tight fit on your darts.

Please answers from experience only. The point of this thread is to end my speculation, not to add to it.

It's pretty rude to be picky about who helps you. Ever heard beggars can't be choosers?

Anyway, the answer to your question without a question mark is no. The dart does not go from a significantly wider area to a significantly more tight area (though the double significance is naturally redundant). It is sitting in the half pipe, but it is only a tiny change. Measure 1/64" for me. That's the size difference that occurs.

Oh, and if you realize you're speculating, shouldn't you have just tried it? They're really not that hard or expensive to make.

Edit: Didn't really mean to come off as blunt as I apparently did. My bad.

Edited by Splitlip, 25 January 2009 - 09:13 PM.

[TantumBull]

Yes, I've heard beggars can't be choosers. I was simply saying that I wanted someone to respond who's done it, like you, because I obviously haven't. And no, I haven't done it yet, because I wasn't about to spend about 10 bucks on brass and PVC, just to find that that breech set up sucks. I'm sorry, I guess I don't like wasting money. Oh, and my question did have a question mark. I simply set up the question with a statement. Christ. Thanks's for the part of your post that answered my question and didn't ridicule my thread, though.

It just really seems like that transfer from half pipe to full pipe (probably not the right term) would hinder the dart. Apparently not.

[Draconis]

I think it may be more of a problem with Slug darts, due to the abrupt perpendicular surface, than with standard round tip stefans.

[rork]

The REBAR (remember it? The gun I STILL haven't posted a writeup for? Gah...) uses a cpvc breech, and the half-pipe that the dart rests in is covered in 1/2" thinwall. The transition poses no problems, even for Slug darts.

[Quilan Fett]

If you are still worried, just make where the transition between the half pipe and full pipe a v shape instead of a flat cut.

[TantumBull]

If you are still worried, just make where the transition between the half pipe and full pipe a v shape instead of a flat cut.

That's an incredibly good idea. I'm gonna try that.

Also I was more worried about the fact that the dart was going to a tighter barrel fit, like if you put tightening rings in the middle of the barrel. I was also kinda worried about the transition though, so thanks everyone.

[CaptainSlug]

I think it may be more of a problem with Slug darts

If your hot glue domes are extending to the very edge then they're not going to perform well because they will have high friction inside the barrel.

Edited by CaptainSlug, 29 January 2009 - 03:27 PM.