Short LA Cartridge in a Big Mag

[SoGaRKTcT]

I've started trying to part out a 7mm PRC Ultralight Hunting build. Was thinking I could start buying parts now and maybe by next hunting season I would have everything together, working and tested to actually use on a trip. But I'm running into problems. The 7PRC has a COAL of 3.34 which is on the shorter end of Long Action cartridges. I am trying to do an ultralight chassis with a folding stock like the MDT HNT26 or XLR. The problem is that for the Remington 700 LA all these chassis are designed for the CIP 3.85 magazine length. So, the action manufacturers I have talked to are saying there will be feeding problems trying to get the shorter 7PRC to feed from the larger 3.85 Mags. What is your opinion on this? Have any of you run ever run some of the shorter length LA cartridges in CIP 3.85 mags and can speak to issues or not?

 

[DownhillFromHere]

Have you been in direct contact with MDT, since you mention their HNT26 chassis as an option and they offer a variety of caliber/length-specific magazines? Easy button would be send them a query via this link.

I would guess a CIP-length mag would feed the 7PRC ok, since the parent 300PRC is only a third of an inch longer - about 10% length difference. I am in process of breaking in a 6BR barrel and do not yet have caliber-specific AICS mags to feed the stubby little cartridge. However, it is worth noting that my regular .308-class mags feed the 6BR fine if I place the rounds as far forward in the magazine as possible - which leaves 0.53" or about 20% of cartridge length of empty space between case head and rear of magazine. Note that I have not tried to run the bolt fast; I can just say that cycling rounds during load development / barrel breaking has worked just fine. I'll also note that placing the rounds far BACK in the mag results in misfeeding - bolt doesn't pick up the round.

MDT's support team is great. Check with them.

 

[Chickentoast]

I've run some short 300 WM's in 3.85 no problem. Also run a 6.5 Max @ 3.07 COAL in a regular LA mag.

 

[Long Range 338]

Shouldn't be much of a problem with the HNT26. Make sure you get the best option for magazines and you may have to adjust the feed lips to work flawlessly but shouldn't be too much of an issue. Lots of guys running 6.5 PRC in a long action making it work without issues.

 

[Rockfish Dave]

Had a "gun smith" tell me 284 shehane would not run from a long action magazine. I built it anyways and it ran fine with zero issues. That was a manners mini chassis stock and surgeon 1086 long action, pretty standard stuff.

 

[LikeADirtBoss]

I've started trying to part out a 7mm PRC Ultralight Hunting build. Was thinking I could start buying parts now and maybe by next hunting season I would have everything together, working and tested to actually use on a trip. But I'm running into problems. The 7PRC has a COAL of 3.34 which is on the shorter end of Long Action cartridges. I am trying to do an ultralight chassis with a folding stock like the MDT HNT26 or XLR. The problem is that for the Remington 700 LA all these chassis are designed for the CIP 3.85 magazine length. So, the action manufacturers I have talked to are saying there will be feeding problems trying to get the shorter 7PRC to feed from the larger 3.85 Mags. What is your opinion on this? Have any of you run ever run some of the shorter length LA cartridges in CIP 3.85 mags and can speak to issues or not?

Old thread resurrection. Was thinking of doing the same thing. Building a 7 PRC in a MDT HNT26 chassis with CIP 3.85 mags. Did it work for you? What mags did you run and did the feed lips have to be adjusted. MDT has 2 mag options, 300 PRC or 300 WM. Wondering which would be the best?
J