First Rifle Build-DBM feed Issues

[James Carini]

Good morning sniperhide,

First post here and sorry if this is the wrong forum for the question, but I just assembled my first rifle and I am having some magazine feed issues.

Rifle is setup as follows:
Jp Apac chassis
Zermatt Origin SA action with 223 bolt face
26” shilen pre fit match barrel in 204 ruger
Using accuracy international & mdt metal 223 mags
Factory ammo

I have go/no go’ed the barrel half a doz times because this is my first time and I don’t want anything to explode on me. The go/no go gauges are good. The bolt cycles, picks up the round from my DBM, but it fails to chamber it correctly and hangs up.

Any input on things to look at? I was told to look at the feedlips on my magazine and tweak them but I’m not sure if I need to open them up or lower them. Looking for some input before I starting bending metal on a $100 mag. Thanks!

 

[Cynical]

Do you have a push feed bolt head or controlled round feed? From that picture it can’t be controlled round feed, and that would be a problem if it was.

 

[James Carini]

Do you have a push feed bolt head or controlled round feed? From that picture it can’t be controlled round feed, and that would be a problem if it was.

The Origin action should be control round feed. Truthfully I didn’t know there was a difference till your comment and I went and watched a video on it. I will have to cycle it this evening after work and watch how the bolt and round interact. The attached could could be deceptive as I had been jimmying the bolt and trying to get a picture at the same time.

 

[Cynical]

The Origin action should be control round feed. Truthfully I didn’t know there was a difference till your comment and I went and watched a video on it. I will have to cycle it this evening after work and watch how the bolt and round interact. The attached could could be deceptive as I had been jimmying the bolt and trying to get a picture at the same time.

They make some special bolts that are push feed. Take your bolt out and see if you can get a case into the bolt head by hand. Zermatt is known for really good service, if you need it. @Zermatt Arms

 

[Jigstick]

Might need to tune the feed lips of the mag. My AIAW mags all needed tuned to feed my 6x47 on a BAT action.

 

[James Carini]

They make some special bolts that are push feed. Take your bolt out and see if you can get a case into the bolt head by hand. Zermatt is known for really good service, if you need it. @Zermatt Arms

Definitely a controlled feed bolt face. So after watching it cycle more closely it looks like the bolt is pushing the round forward but the case is popping up/free of the mag and not catching in the bolt face and then thr shoulder jams on thr chamber.

I reached out to Zermatt and waiting for a response

 

[JR1200W3]

You need to adjust your mag feed height. A controlled feed action requires the extractor to pick up the case rim in a very specific phase of feeding. The case rim needs to slide up under the extractor while the bullet rides up the feed ramp. The key to this is mag height in the chassis set by the latch. I've run 223 out of a TL3 for 7 years from XLR and MPA chassis with zero problems

 

[James Carini]

You need to adjust your mag feed height. A controlled feed action requires the extractor to pick up the case rim in a very specific phase of feeding. The case rim needs to slide up under the extractor while the bullet rides up the feed ramp. The key to this is mag height in the chassis set by the latch. I've run 223 out of a TL3 for 7 years from XLR and MPA chassis with zero problems

Thanks for the input. I didnt see any immediate adjustability but I’m assuming if I pop the roll pin holding it in place it has a set screw? Not sure if you have any experience with this chassis?

 

[JR1200W3]

Thanks for the input. I didnt see any immediate adjustability but I’m assuming if I pop the roll pin holding it in place it has a set screw? Not sure if you have any experience with this chassis?

I don't. Sorry.