Reloading? Whats going on here? Any Idea? Pic up

[Tactical30]

I had just got into reloading and recently built a 6.5mm Grendel on a AR style platform (i have built many ARs) and put a Sabre Defense 18" Competition Deluxe bbl and bolt that came with it. I have yet to shoot <span style="text-decoration: underline">ANY</span> ammunition thru it. It was near impossible to find some factory ammo at the time so i got the reloading components for it cuz it was in stock. (Lapua Brass, Rem. 7 1/2 BR Primers, 123gr. Sceanars) It seems there isnt much freebore in the barrel. What was odd is I had reloaded some rounds according to Alexander Arms Specs and when i loaded some 123gr. Scenars it seemed like they were getting slightly stuck in the lands. The factory OAL for those are 2.265" i had seat them down to 2.220" to fit with no sticking. Then for the hell of it i loaded an empty case with a 123gr. Scenar seated at 2.265" the next day, slammed the bolt and it didnt stick. What the hell is going on i thought. I talked to alot of guys on 65grendel.com and nobody had had this problem. Someone said that AA make their bores with a "compound throat" meaning there is no freebore, "fooling the bullet" and all of the rounds are "supposed" to pig-jam. I never heard of that before. Does the barrel/chamber/bore need fireformed/broken in with factory ammo? I have some AA 123gr. Factory ammo on order, When that comes im going to see what it does. I just dont know why when the first time I reloaded them they were sticking then the second time i reloaded them they didnt.This happened with 2 different rounds and 2 different OAL's and i didnt resize the brass, I did nothing different. I dont get it. Does it have anything to do with me screwing up brand new lapua brass by FL sizing it when i first got it? By the way something i will never do again. Also when i looked down the chamber it doesnt look like there is any freebore at all. Is this normal for AR setups? I have Reloaded hundreds of rounds for my .223 AR and never had this problem. The thing is i would have never known this if i wouldnt have ejected that loaded round. Should I just load some rounds up to AA specs and go shooting or wait till i get the factory loads and let those loose? Whats the going on here?

 

[mattmcg]

Re: Reloading? Whats going on here? Any Idea?

Hmmm, tough to tell given the data you've presented. I might suggest picking up the Stoney Point (now Hornady) bullet seating depth checker tool. It's cheap and you'll be able to measure your base to ogive length accurately for the chamber in your rifle and from there you can determine any issues with proper seating depth on reloaded or factory rounds. This will give you the empirical data to truly trouble shoot your problem.

As to speculation, perhaps a round was out of spec and was loaded long? Other than that, don't know what to say......

 

[Tactical30]

Re: Reloading? Whats going on here? Any Idea?

Here is a casting I had done. No Freebore.
Im betting tho if i fire 500-1000rds of factory ammo it will wear enough to reload to OAL (i.e. 2.265")

 

[mattmcg]

Re: Reloading? Whats going on here? Any Idea?

Wow, very interesting. I haven't seen that before. I'm unfamiliar with the round so can't say whether that is OK or not. Did a gunsmith chamber this for you? If so, I'd definitely place a call and see if the chambering is correct.

Good luck. Interesting problem for sure.....

 

[Tactical30]

Re: Reloading? Whats going on here? Any Idea?

It came straight from Sabre Defense like this.
I sent an email to Bill Alexander at AA about this.

 

[Country]

Re: Reloading? Whats going on here? Any Idea?

Its hard to tell but there may be some free bore and taper throat . I would do a few tests with seated bullets in an empty case just to work out what you can chamber and what you can't. If any factory rounds don't chamber then it can't be right . You don't want bullets jaming into the lands in an auto I don't think anyway .

 

[Sig685]

Re: Reloading? Whats going on here? Any Idea?

Now this is an interesting problem and please do not take anything I write here as reality, I am just thinking out loud. Emailing AA is a great idea and if they do not answer today, I would get on the phone; they will have the best answer (and it is hoped, the correct one.) On the other hand we can speculate here and have some fun.

My first thought was "what does you finished round look like? And what does a factory round look like?" Ok, I admit, that was two thoughts.

The next one after seeing the photo was "there is some freebore, it's just not very long, and that grove starts of very shallow."

As you know, grooves do not start at full depth right away, or rather the lands don't. When the rifle is chambered, the reamer will smooth out the lands right in front of the throat and give the lands an angle. You can see it in your picture, so I'm wondering if that is what your guy on 65grendel was talking about with respect to "compound throat". Sounds like a fancy name for an angle.

However, to me that says that the chamber is probably formed as it is supposed to be because the reamer did its job on the lands also. The reamer is one tool that does the chamber, neck, throat, freebore (or leade) and the angle on the lands. It's one unit. Here is an example:
http://www.pacifictoolandgauge.com/products/reamers/chamber.htm#solid

So, all this to say that you most probably have a properly chambered upper, BUT again, this time you did the right thing and contacted AA. I would wait for their reply and I, for one, would love to read what they have to say; I am always learning.

 

[Tactical30]

Re: Reloading? Whats going on here? Any Idea?

I am thinking also that "maybe" if I shoot 500-100rds of factory ammo it should "break-in" or open up the throat/freebore enough to be able to fit some reloads but if im loading reloads at the factory specs whats the difference? Same size OAL,Same Brass,Same bullet. That what I keep hearing people say is" Shoot a bunch of factory brass thru it to open it up." Then again i have never built an AR and the first rounds I shot were reloads they were always factory ammo but again there should be no difference. Another thing ALOT of factory ammo is seated to fit everybodys chamber so its always seated deeper. Everydodys chamber different too, so I dont know what to say.

 

[Top Cat]

Re: Reloading? Whats going on here? Any Idea?

OAL and ogive length are two different measurements...freebore and chamber throat are two different designs.

Ideally, a loaded round should be a few thousandths short of fully engraving the rifling, but with the way that your throat is cut, depending on the true ogive length of the bullet and actual diameter of the bullet, you may not be able to avoid slight contact with the lands. You may have a match reamed chamber in your barrel. A snug throat can help with accuracy but may cause pressure spikes.

The factory OAL number you are referring to may be most relevant only to a specific lot # of bullets. Ogive length will vary somewhat even within a box of 100 bullets. That OAL they are reporting is what happened to work for them. Mostly in an AR, the max OAL will be limited by what will fit in the magazine.

Consider that AA developed their data with particular lots of bullets, brass, primers and powder, and that all published reloading data is a guideline to start out with, not a prescription to blindly follow...apply the data with common sense...your box of Scenars may have a slightly longer ogive, or your chamber may be a hair shorter...that's life, and that's one benefit of reloading, to load rounds that fit your chamber correctly.

Anyway, at this point you don't want to jam the bullet hard into the rifling, but a slight contact with the lands where the cartridge is easily removed without moving the bullet in the case is not really jammed.

With a small capacity case like the Grendel, small variations can cause over pressure issues. This applies to different brands of cases, bullets, and especially powder lots, so the general rule is to always start by working up your loads at least 10% under maximum loads and work up from there.

AA's starting load data is not always sufficiently reduced, in my opinion, to reflect that basic safety rule, but if you use their data, pay attention to what they consider to be a max load and follow the general rule above. If you do that, you should be ok even if you have a rifle with minimum headspace and a tight match throat.

I hope any of that makes some sense to you and is helpful.

TC

PS Where are you in PA?

 

[Tactical30]

Re: Reloading? Whats going on here? Any Idea?

I live in Western Pa, a little town called Hermitage, Its about 65miles north of Pitts. What you said does make alot of sense. Thanks

 

[former naval person]

Re: Reloading? Whats going on here? Any Idea?

I have no idea what AA's practice is, but a common practice is to start out with a max reamer and sharpen till it reaches minimum specs. Your chamber's throat may have been cut with a reamer that has been resharpened to minimum dimensions. However, since it is a handloading proposition, do what TC recommends...as it wears you'll be able to "chase the throat", thereby maybe giving you a longer service life. JMHO

 

[Top Cat]

Re: Reloading? Whats going on here? Any Idea?

Some folks will spend a lot of money on a factory rifle just to end up with a tighter throat and enjoy the benefits that will bring, one of those being using a shorter OAL. Throat length does increase with the round count, all too quickly, it seems.

AA can answer the question for you as to what their design philosophy is regarding the Grendel to see if you have an issue, but use all the info you have at your disposal to create the best fitting ammo for your rifle over time.

I've heard of Hermitage, but I've never been there. I grew up in a suburb of Pittsburgh, the reason I asked.

TC

 

[Tactical30]

Re: Reloading? Whats going on here? Any Idea?

I seen s a Pacific Tool and Gauge uni-throater hand throating reamer for sale for a (.264) 6.5mm/ High Speed Steel. I dont know if this would help but im sure it would with making some extra freebore. Im sure there is a better Co. that makes one too.
I have never used one of those before so im sure I would have to have a g-smith do it. If you could do it to that barrel, I dont know. I got some factory 123gr. Lapua scenars UPS today. Im going to see what those to at the range. I chambered one of them and it semmed like the bullet just barely comes in contact but ejects easy so I shouldnt have any problems.