Loaded M1A...to throat or not to throat?

[sdcitizen]

M1A, what a great rifle, had one for a year now, and with the copper coated stuff, it shoots lights out, couldn't be happier with it. The problem is it just never wanted to reliably chamber cast boolits. It would seem like I had ammo loaded short enough to freely chamber, head to the range and get 3, maybe 6 rounds downrange and it would begin not fully going into battery. Tried seating shorter, to make sure, very sure it isn't touching the throat, (with some loads this was an OAL length of 2.65 or so) STILL won't reliably chamber. Maybe the brass in the neck is too thick, so switched to Winchester headstamp brass and sizing to .309 this removed .003 to .004 from the neck diameter, still won't reliably chamber.
Finally broke down and did a pound cast according to the Goodsteel method, AHA! The throat starts at .311 dia, and halfway between the start of the throat and the start of the rifling, it abruptly steps down to .307, which is bore dia. So the question is, is is worth it to rent a throating reamer and clean up this area, with the chance of reducing its accuracy potential with jacketed, in order to be able to shoot cast? If I did this I would likely shoot 90% cast, maybe even more often, and if it is fairly likely to maintain 1.5moa with jacketed loads, that would be plenty accurate. Any thoughts on this? My current plan is to order the reamer on Friday or Saturday and give it a try.

[DougGuy]

I think you are on the right track and no it won't hurt the accuracy with j-words. DO get a live pilot reamer if you can! The difference in concentricity over a solid pilot is night and day different. Solid pilot that is small enough to be wiggling in the rifling ain't no way to do it if you really want it done right. I would call Dave Manson (eight one zero - 953 - zero 732) and see if you can get Dave on the phone and pick his brain some. He makes beautiful reamers and may have one with the perfect taper and a few interchangeable pilots that you could later resell and recoup most of your investment, in the long run you would spend less than the rental and have a MUCH better tool IMO than a solid pilot reamer.

[missionary5155]

Greetings
Doug has very good advice on the reamers. Anther advantage is you can longer seat heavier bullets to mag length if they will not now.
Me if my rifles will not shoot cast well they are of little value. My M1A (Fulton) handles the RCBS 180 FNGC like a dream. It will easily do 2 MOA with most any powder in the correct burn rate. Refined loads get some better. This is at 23-2350 fps. Easy on the rifle and no human shoulder problems later. I shoot very few "j thangs" and have little desire to. But it sure is enjoyable to take out 200 rounds and ring the 300 yard gong and not feel like I have blown my shooting budget for the whole month. Just to many other fun caliber .30's to keep warm also.
Mike in Peru

[sdcitizen]

DougGuy, that's just the sort of help I was looking for, thank you. I will have the pound cast in hand and try to raise Dave Manson tomorrow, hopefully he can find something that will be just the ticket. Mike, if I could get 2moa at 2000fps, I'd be tickled pink; if I had your results, its likely I also would never go back to jacketed.

[sdcitizen]

A little update, after talking with Dave Manson on the phone, he thought the standard pilot would be pretty close to right, so I bought one. After reaming the throat, preliminary testing shows perfect functionality and at no apparent loss of accuracy, will be out this weekend to put it on paper with the go-to load of 32.5 H335 behind NOE's 313414. Thanks again for the help, I now have a reamer to lend out if anyone else should happen to need it.

[Larry Gibson]

Is your chamber/barrel chrome lined?

Larry Gibson

[sdcitizen]

Hmm, not a clue, I did not consider this, I will check with Springfield. It cut surprisingly easy, I bet a total of 12 revolutions with very light pressure was all it took to get a pound cast that had the step in the throat removed.

[Larry Gibson]

If your barrel is a new commercial barrel it probably is not chromed. If a military barrel it is.

Larry Gibson

[sdcitizen]

The rifle was new as of last spring. Probably one of the best purchases I have ever made, and any information I could find says that after 2004 Springfield quit using surplus chrome lined barrels completely.

[DR Owl Creek]

My bought my Springfield Armory M1A "loaded package" rifle in 2000. It has a stainless steel barrel. All of the loaded package rifles I've seen have had stainless barrels too.

Dave

[Fishman]

What diameter is the pilot? Looking forward to a range report. I need to do this to my .300 blk and would like to take you up on your kind offer if the pilot diameter is correct.

[Larry Gibson]

If stainless then throating, if that's what you want to do, will not be a problem,

Larry Gibson

[sdcitizen]

Its carbon steel, two close friends also have loaded models, and theirs are stainless, this one is not though. Saturday is the big day for the range report. Per Dave Manson, the pilot is between 0.2990 and 0.2995, I come up with 0.2994, but as a not machinist, I am always suspicious of absolute measurements. It fit very snugly in the bore, took a few turns to get the flutes to start cutting.
I wasn't keen to be removing material from the area that takes the most wear on a barrel, but if it just won't shoot cast, something needed to be done.

[sdcitizen]

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Ok, so range testing wasn't wholly disappointing, the first image is of the actual boolit used and seated in a case (noe 311414) sized to .309, coated in smoke4320's gloss black and seated to 2.650 OAL. The second photo is a 5 shot 'group' fired at 100 yards, today at the range was windy, and cold, probably 40 F, and I didn't bring gloves. The third photo is two different groups, the one on the left being seated longer at 2.750 OAL, after cutting the throat, this is as long as the boolit can be seated to chamber most of the time. Velocity on these loads ranged from 2209-2260 FPS, and alloy was straight wheel weights, water quenched, then powdercoated and allowed to cool in the oven.

I didn't actually measure any of the groups, though I would say around 5 inches is pretty close. Believe it or not, this is plenty of accuracy for the 3 gun match I plan on shooting it in tomorrow. Future testing planned will be testing dacron filler to reduce charge amount and still get reliable cycling, and possibly doing a better job of culling boolits with defects, and maybe even weight sorting them. Though for 18 cents per shot, I am happy with how things are currently working, 50 rounds down the tube, and not a single problem, hooray! If anything in the future shows better promise, I plan to move to the standard 10 shot group for accuracy testing.