Lee Loader

So tell me if I'm nuts for expecting too much, or if I'm just having a bad stretch of luck.

After Christmas I bought a 6mm Mongoose barrel to put together a long range varmint AR-15. It was suppost to be a premium quality barrel.

Here's the chamber cast. The pictures are of opposite sides.





I returned it for a refund and then bought a cheap no-name 6.5 Grendel barrel. Premium, ISO quality, blah, blah...

Here's the chamber cast. The pictures are of opposite sides.





I returned that one for a refund and figured that the AR parts are a crap shoot and so I decided to just get one of those nice Howa Mini rifles in 6.5 Grendel. I have one in .223 and it's a jewel.

I shot one round tonight and had a tough time lifting the bolt. The neck cracked. Yea, it's a cheap steel case. It's what I had on hand after dialing in my brother's 6.5 Grendel AR. But he hasn't had a single problem in over 500 rounds.

Anyway, here's the Howa chamber cast. Again, the pictures are of opposite sides.







In my work fitting cast bullets I've not encountered chambers like this. I've even rechambered several myself by hand and never cut anything like this.

So, is it me expecting too much? Has anyone run across anything like this before?

If you are certain that it is not problems with the CerroSafe or something like lint from patches left, then yeah, that's nasty! Do you have a borescope for your smartphone? If so, what do the pictures of the chamber look like? The only way Howa could get the rifling cut they did was if the chamber cut is non-concentric. With the borescope, you could snap a picture, easier to email them than send the chamber cast.

If you don't have a borescope, get one.

Almost look like cut with same reamer. I am not familiar with the wildcat but are the reamers propriety?

I have a bore camera, but the resolution is poor - especially at 90 degrees to the bore. How is the resolution at 90 degrees with those smartphone cameras?

Each chamber cast was done several times to make sure I was doing it right. All looked the same for each chamber. This Howa I did it twice with the rifle in identical positions and then did an impact cast with a soft lead slug and all were identical.

The first barrel is a 6mm Mongoose made in USA.

Second is a 6.5 Grendel made in USA.

Third is a 6.5 Grendel made by Howa in Japan.

It sounds as though you have it covered, now what are you going to do?

The borescopes have a pretty good view as you move it through the barrel, but I just realized that they wouldn't do you any good. They are too big to get down a 6.5mm barrel.

Matt at LSI Sports saw my posting on the Grendel forum and asked that I email him. I did this evening.

I chambered a number of different bullets tonight in an empty piece of brass and the 120 gr bullets engrave hard on one side unless seated very deeply. The 100 gr Hornady SP chambers fine with the base of the bullet at the base of the neck. I loaded a couple of rounds of 100 gr and shot them over the chrono and the brass looked fine and the velocity was in line with the loading data. (2650 fps) But they will hit the rifling crooked so no telling how accurate it will shoot. I really want to shoot the heavier bullets for their better BC and downrange energy.

That's good that LSI reached out, is this for the Howa? Maybe they will replace the rifle.

Being the curious sort I find this post really interesting. Three barrels all with the same apparent defect. Are the barrels in each case hammer forged? (the Howa site says they hammer forge.) Was a rough chamber part of the forging or was it cut separately for all of the barrels? A bit of mystery to be sure. Hopefully you get some answers.

LSI is the Howa importer. The other two were barrels for an AR and I've already received refunds. Of course, being a rifle, the Howa will be a bigger hassle. I'm guessing that they will replace the whole rifle rather than replace the barrel which will mean another ffl transfer fee.

From what I gather, a lot of chambers are cut on cnc lathes with single point tooling. If the barrel is not centered on the bore, the tool goes in at an angle and produces the results you see in these chambers.

The Howa is supposed to be hammer forged, but if you look at the shoulder area of my chamber cast you can see ridges. I can feel these ridges on the cast with my fingernail. There are also rings on the shoulder area of the fired case. In my limited experience running a lathe, this was cut with dull tooling and/or too great of a feed rate. I'll ask LSI how it was made when I hear back from them.

Thanks for the info! Makes me glad that I spent my 7.62x39 money on the target cam.