Range Report AIA #4 with Bedding Info

Ganderite

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In an earlier post, I noted that a newly acquired AIA (Australian commercial #4) was shooting large groups. On investigation, with the top wood removed, I could see that the barrel channel was pushing on one side of the barrel. The barrel channel was opened and the action bedded in Devcon F.

Yesterday the rifle was tested at 300 yards. I loaded military 147 gr. surplus FMJ bullets, Sierra 155 match and Sierra 168gr match bullets, with 4 different powder charges of H335 for each, in 0.5 gr increments. I used H335 powder so I could throw the charges with a degree of accuracy. OAL was 2.825” my standard length if I want ammo to clear the magazine.

The results were quite clear. First, the rifle shot better. Groups were round, with a slight left-right bias reflecting the gusty light wind while we were shooting. We shot groups at black patches, stuck on the back of a large target. A buddy in the butts pulled the target after each group and labeled the groups with rifle and ammo. He also put a red spotting disk in the middle of each group so the shooter could shoot groups that did not over-lap. Walkie talkies are handy.

Second, and most interesting, was that the military surplus 147gr. FMJ shot much larger groups than the match bullets. They will be ok for shooting 100 yards from the standing position, but not for anything calling for any accuracy.

Third, was the rifle clearly shows the tendency to the #4 to “compensate” and shoot tall groups. At a longer distance these “tall” groups will come together. I won’t likely test at long range to see what loads works at, say 1,000 yards.

The ammo was loaded in half grain increments and for each bullet it was clear that some groups were “tall” and some were very flat. The “flat” loads will be noted as the best short range loads for this rifle.

GROUPS SHOT AT 300 YARDS

147gr FMJ
41.0 3.5”
41.5
42.0 5.25”
42.5 7.5”
43.0 11.75”
43.5
44 9.0”
Note to self: Try 39 to 41 for a good plinker with these cheap bullets. Milder seems to be better.

155 Sierra Match
40
41 3.8”
41.5 1.25"
42 4.3"
43 3.8”
44

Sierra 168 Match
39.0 3.2”
39.5 4.2”
40.0 2.6”
40.5 1.425”
41.0 1.4”
Note to self: Try hotter loads. Hotter seems to be better. These are sub MOA loads. Also try 190 gr match

RANGERESULTS300YD2-1.jpg


Lesson for newbies:
• Some bullets work better than others in a given rifle.
• A little more or less powder can make a big difference.
• Bedding has a profound effect on accuracy and consistency.
 
Last edited:
Ganderite, any advice on bedding the LE?

I have dug up some info on the internet, but it is armorer level stuff and seems very complicated. I've got experience bedding things like Mausers and modern bolt actions, but no LE's.

Thanks!
 
Bedding the LE is a bit different than the Mauser and other rifles. I have bedded quite a few LEs used by members of the Rifle Team at Bisley. One learns what works and what does not.

The recoil lugs are a pair of angled lugs near the rear of the action. I chew away 90% of the top part of the wood, so that the bit remaining locates the action in the wood and the tenth of an inch of Devcon F putty gives perfect contact withthe lugs.

Around the front action screw, I remove the wood to a depth of at least a tenth of an inch and also drill some holes to "anchor" the bedding. Again, i leave enoth wood to locate the action at the correct height.

AIABedding2.jpg


The above is not all that unusual, compared to what you have done in the past.

Here is what is different. I lay two worms of plactercine across the forend channel about 4" back from the tip and put a blob of bedding material there. The wood is not prepared or roughened in any way to accept this blob. It will be knocked out, later. When the forend is installed and the Devcon hardens, the barrel will squish the plastercine and Devcon down, so as to leave a small pad of bedding under the barrel, with zero up pressure on the barrel.

AIABedding3.jpg


After the bedding job has been done, the forend is removed. It is critical you do not remove it by prying down on the forend. This will break the recoil lug bedding pads. Use a block of wood to tap downwards on the wood, beside the action. The wood comes off, straight down. I often fire a few rounds first, to make sure the Devcon has released from the metal.

When the forend is off, prepare the tip of the forend for another pad of Devcon. This pad is in front of the temporary one. Lay two worms across the wood and put in a big dollop of Devcon. PUT A PIECE OF AMMO BOX CARDBOARD ON TOP OF THE TEMPORARY PAD. This will put up pressure on the barrel. The new Devcon pad will harden in place with the barrel pushed up about 50 thou.

AIA3084.jpg


After the Devcon has hardened, remove the plactercine worms, the cardboard and the temporary pad. The barrel will now have a couple of pounds of up pressure on the pad.
This is what I did to this rifle. The result is 300 yards that went from 8” to under 2” (under 1 MOA) with the right load.

Before bedding

A1ABEFOREAFTER.jpg



After bedding

A1ABEFOREAFTER1.jpg
 
"what kind of tape measure do you use?"

For simplicity and record keeping, I only record the vertical of a group, on the theory that in a no-wind situation, groups would be round.

If the group is wide, on a calm day, then I note that as a bedding issue and deal with it.

On this day there was a gusty fishtailing wind, so I expect the groups to be wide. The group sizes noted are vertical only.
 
Right on, I was actually referring to your 1/10 of an inch comment.... I'm a carpenter and tend towards 1/8, 1/16 of an inch.
Thanks again for sharing your techniques and experience!
 
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