Re: Need some thoughts here.
Being the owner of ARs with 16.1, barrel, two with 20" barrels and one with 24" barrel I can say none of them would be suitable for what you are talking about (carry in back pack).
As well if you take a bad fall or the pack does the chances of it breaking is pretty high. I have seen the AR broken in half and in fact did it myself once on a four foot drop. Does not give you a good feeling I can assure you not to mention the fact having a two piece lower receiver is not conducive to firing at all.
I assume you are talking about the ability to retrieve it fairly quickly and get it going in either a social event or undesired interest from the animal kingdom.
I have thought long and hard on this very thing for several years and have decided the ideal "pack" rifle would be a 1903/A3 Springfield with stock cut off about an inch to the rear of the pistol grip and barrel at 16.5" with a AR flash suppressor installed. On the flash suppressor I would have a cap plug to keep muzzle clear of dirt etc. The stock would be cut about one inch in front of the action as well.
The barrel configuration would be cylinder for perhaps three inches in front of the receiver then reduced to about .700 diameter?? (Same diameter as a Thompson Contender Super 14.) On this cylinder diameter I would attach a Thompson Contender Scope mount by Weaver. Barrel would be stainless. There is no reason why the 700 diameter could not continue to the muzzle.
Scope would be a NC Star pistol scope which in my experience have proven quite rugged and reliable. Or a red dot of your choice.
You will appreciate the scope as when you hit middle age the iron sights will be harder to see.
You could also mount a set of sights from a Remington 700 with rear sight over the chamber and at the muzzle or turn the muzzle to accept a M1 Carbine sight which would be even more rugged.
There are several calibers it could be used with from 243, 260, 7/08, 308, 30.06 and 358 Winchester or 35 Whelen. Any of these calibers is going to give superior terminal ballistic performance than would the 5.56 round. It has a five shot mag and a round can be carried in the chamber as well (safety on) making it a six shot.
I can't imagine anything a 260 thru 35 Whelen won't impress with one hit. My immediate thought is to make mine in 358 Winchester with 14 twist for several reasons. I can load relatively low report rounds loaded with 300 grain cast bullets departing the muzzle at 1100 fps. In the mag at the bottom would be full house 300 grain bullets running what it can generate because if it gets down to that, sights/scopes mean nothing.
I also have a 222 gr. 357 mold and Col. Fackler of the Army Wound Ballistics lab said this bullet at 800 fps would go slam through the biggest guy I could find. Thusly a 300 grain bullet at 1100 fps would be very effective on anything so applied.
As one book I once read said, "At ten feet with a target the size of a pie plate, I can hold my own with anyone."
As well in 308 one could load 200 grain cast bullets for low report and bottom of mag would bring up 150gr. FMJBT which is one of the highest lethality rounds ever developed for military applications.
Assuming you are proficient with firearms this combo should give hard hitting performance at longer ranges and devastating performance at point blank range.
If you have to you can use it as a club in a final defensive posture.
With the scope assuming you have good loads it should give superior accuracy over a light AR which is obviously very delicate even more so in a "lightened" condition.
Assuming the barrel at 16.5 inches and the length of the action and the grip of the stock you should easily attain 26" OAL as required by federal law.
You could attach a lanyard to the butt area of the stock for hand carry or sling over shoulder. With a little development work a buttstock could be screwed into a plate on back of stock.
If the muzzle area was turned to the correct diameter a M16 bipod could be used for long range work attached directly to the barrel.
This configuration is closer to the little Guide's Rifles made years ago but this one has superior ballistic performance. Another little rifle is the Marlin 30-30 made for kids which has a short stock and short barrel and is very neat. I think it was called a Buckhorn??? Spikehorn??? I could not see the sights(tad over 40) but I recognized it as a very neat little rifle and with a red dot scope dangerous at 200 yards.
The 1903 could be held forward with both hands in the same manner metallic handgun silhouette shooters hold their weapons.
