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Boys Anti-Tank Rifle - Ordnance Board Reports


Ordnance Board reports on trials of the Parker-Hale sub-calibre conveyor training system

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Here follow facsimiles of the correspondence on the subject. The first communication on the trials of the conveyors is dated 8th. April 1940. The last available memo is dated 21st. August of that year. It will be seen that the trials were quite comprehensive, and the reports are self-explanatory. Comment on the mathematical content would be practically superfluous, but it is evident that, whilst the disadvantages clearly show themselves, the benefits of the system, in spite of its limited accuracy, were overall deemed to outweigh those limitations, particularly in view of the reduction of paraphernalia associated with the alternative system, at that time, of clamping a Lee-Enfield No.2 Mk.IV* training rifle to the side of a Boys ATR (as illustrated on the main page for the ATR) and which had been described as an "encumbrance".

 

NO. 5,747 (contd.)
47-4-40
8. 4. 40, to Sec. O.B.
These conveyors have now been tested and report is forwarded herewith. it is thought that as a training device this method is more realistic than the 0.22 inch rifle attachment as :—

  1. Rounds are fed from the magazine by normal bolt manipulation.
  2. Actual trigger pressure is taken. 3. Realism is not obscured by the encumbrance of the 0•22 inch rifle and fittings.

Accuracy is poor due to the shortness of the " barrel " and is also dependent on the fit of the conveyor in the chamber of the rifle.
Only three conveyors have been tried and it is pointed out that it would be essential in mass production to maintain the same precision of manufacture. Unless the bore of the conveyor is exactly concentric with that of the rifle, the 0.22 inch bullet might strike in the barrel or muzzle brake of the parent weapon. It is also considered essential that these conveyors should only he used with a new or comparatively new barrel, as if the chamber is worn the trouble mentioned above is again liable to occur from this cause. Damage to the striker is likely to occur from continuous impact with the auxiliary striker, and this trouble would have to be watched for by armourers.
These conveyors are considered an improvement over the 0•22 inch rifle attachment as a Boys rifle training device, but it is considered that the opinion of the Small Arms School should also be obtained.

REPORT.
These conveyors are similar to those designed by this firm for use in 0•303 inch weapons, except that due to their length they are rifled and act as barrels. Consequently the parent gun is not tubed and its bore is merely a clearance hole through which the 0-22 inch pellet passes.
The method of firing is by means of an auxiliary striker which is inserted into the
base of the conveyor after loading with a 0-22 inch cartridge. This is the same in principle
as the method used in the 0.30 inch U.S.A. " Zip " cartridges recently tested. Results.— A few diagrams were taken at 20 yards range and accuracy is poor. This is probably due to
:-

  1. The shortness of the " barrel," about 4 inches.
  2. The positioning of the " barrel " depends on the fit of the conveyor in the rifle chamber..

Difficulty was also experienced at first due to missfires, these were cured by fitting a heavier striker spring which is now standard, but was not used on the earlier 'rifles of which this is one.
Conclusions.—This system suffers from the same disadvantage of other sub-calibre systems, in that the firer experiences no shock or blast effects. It also introduces the same risk of damage to the striker as the " Zip " system.
It should be noted that, as received, the conveyors, due to their shape at the front end, would not feed into the chamber from the magazine and were slightly modified to endure correct feed.
Accuracy table.


Fired on pistol butts at 20 yards.

Rounds fired.   No. of conveyor     Rectangle.       
                                                        inches.

Ammunition.—I.C.I. '39.

Remarks.

3=10

3. -I k 5

2.8x 3.4

For 10 rounds.

5

1

1.6 x 1.8'

 

:5

5

22 x 0-7

 

6

3

2.6 x 1.6

Rectangle for 5 shots.        1 shot off.

 

 

3.3x 2.3

Rectangle for 15 shots.

5

3, 4 & 5

 

From magazine.

Advanced Action, 12. 4. 40. Forward to D. of A.

  1. This method of firing sub-calibre cartridges shows some promise. but it remains to be seen whether the accuracy obtainable is acceptable for training purposes. The Board will ask Comdt. S.A.S. to carry out further trials in both new and worn parent rifles.
  2. Ask Comdt. S.A.S. to test this method of firing sub-calibre rounds from both new and worn rifles and to report on its utility for training purposes.

Inform him that the trial should be carried out on high priority.
3. Secretary to arrange for the conveyors to be forwarded by C.I.S.A. to Comdt. S.A immediately.
Action.—The Board confirm Advanced Action taken on 12. 4. 40.

 

NO. 6,016 --6-0r3-- 113`).            SECRET.
1540

 

103/0/17 110/1/3/1 110/1/14/1

RIFLES.
Boys 0.55 inch.
Parker Hale conveyors for sub-calibre firing.

Previous No. 5,747/


Comdt.       1f. 40, to Sec. O.B. (re No. 5,747).
The trial has been carried out at Hythe and the following is our report :—
As a training device this method has many advantages over the 0.22 inch rifle attachment. It has been found, however, that in practice its accuracy is nothing like that required, and it will be seen that the rectangles as per the following table are very poor.
In order that this device should be of value in training, its accuracy must reach a standard of not less than,—
1-inch group at 15 yards, or 64 inch group at 100 yards.
If the device will not give a performance up to this standard, it would mean asking a firer to place the shots in a circle on the target, which the weapon itself is not capable of doing. This will readily be seen from Pamphlet No. 18 (Supplement), S.A.T., Vol. I, where the dimensions of the targets for 1/5th scale and 1/30th scale shooting are shown.
After firing tests had been carried out, the armourer staff sergeant inspected the A/T rifle and found that the recoil reducer had been struck several times and very slightly damaged.
It will be noted that a few rectangles were fired with the recoil reducer removed. This did not, however, produce any marked difference in accuracy.
It seems a pity that this device could not be made to shoot straight as, undoubtedly, it would be the better solution to sub-calibre firing.
It should be noted that the A/T rifle sights are about 2 inches offset so that, even if this conveyor were really accurate, a re-drawing of, at any rate, 1/30th scale shooting targets would be necessary.
Accuracy tests with the new rifle and the old will be seen to show practically no difference.
It is my opinion that the fit of the conveyor in the rifle chamber is not tight enough, and this seemed to be the same in both new and old rifles. Whether a 4-inch barrel can ever give the required accuracy should surely be a known factor ; the D.S. of E. considers a 1 inch group at 15 yards to be a high standard for such a length of barrel and is doubtful whether it can be attained.
Will you give instruction for the disposal of the conveyors.
Summary of firing trials.


Rifle.

Range. yds.

No. of conveyor.

No. of rounds.

Size of group. ins.

Remarks.

New.

25

4

5

4 x5½

In open.

,,

25

4

5

3x6

.,

 

25

3

5

2x5;

 

/,

80

5

5

16 x 8

 

15

4

5

3x3

Indoors.

71

 

 

 

 

 

,,

15

5

5

2 x I

Recoil reducer removed.

15

5

5

21x2

Normal.

,,

15

3

5

3)(1

 

>,

15

5

51¼

 x 1

Each round placed in same position in chamber.

Old.

15

5

5

3x2½

 

,,.

15

5

5

22x it

Without recoil reducer.

,,

15

5

5

2 X I

Each round placed in same position in chamber.

 

15

3

5

3x21

 

Action.—Forward to D. of A.

  1. The maximum length of the conveyor is limited by the size of the magazine, and the Board are very doubtful if the standard of accuracy required (" X " above) can be obtained consistently with an effective bore length of about 4 inches.
  2. The size of group obtained when the conveyors were placed in the same position in the chamber for each round shows that it should be possible to improve the accuracy in normal shooting considerably by improving the fit of the conveyor in the chamber and ensuring that the rifling of the conveyor is co-axial with the outside of the conveyor.

[3. In


NO. 6,016 (contd.)
3.5.40

  1. In view of the great advantage of this method of sub-calibre shooting over the 0.22 inch rifle attachment, the Board will continue trials to see what degree of accuracy can be obtained by a better fit of the conveyor, and in the meantime suggest that con­sideration be given to the possibility of lowering the standard of accuracy required by altering the size of the target used.

Will D. of A. consider this.

  1. Ask C.S.D., in collaboration with Messrs. Parker Hale, to prepare a design of conveyor for the 0.55 inch rifle, which will give the tightest practicable fit in a new rifle. Inform him that., since it is essential that the " bore " should be as nearly as possible co-axial with the outside of the conveyor, it is suggested that in manufacture the bore should be machined first and the outside turned, using the bore as a centre.

Ask C.S.D. to arrange for the manufacture of ten conveyors to the new designs and to issue them to Comdt. S.A.S. (Hythe) for trials. Priority P*.
5. Ask Comdt. S.A.S. (Hythe) to carry out further trials with the new conveyors. Ask him to return the conveyors now with him to C.S.D. (Enfield Lock).
Forward to C.I.S.A A. for information.


No. 6,783 .See 7598                                      611c
2701 Ammunition/ 47         12.6.40
103/0/17             RIFLES.
110/1/3/1             Boys 0.55 inch.
110/1/14/1             Parker Hale conveyors for sub-calibre firing.
F        Previous No. 6,016.
D. of A., 13. 5. 40, to M.T.2 (re No. 6,016).
If this simple training device for 0.55 inch Boys A/T rifle can be made to work, it will confer many advantages and will be easy to produce and requires no fitting to the weapon like 0.22 inch or air rifles. It may not be possible to attain extreme accuracy with this device, and in view of the simplicity of the device some lowering of the standard may be justified. Will you consider this.
M.T.2, 19. 5. 40, to D. of A.
We consider that this device offers great advantages from the training point of view, and we do not think that absolute accuracy is an essential before it can be adopted.
We consider the standard of a 1 inch group at 15 yards is too high to expect from such a device, the main advantage of which is not that it is entirely accurate, but that it enables practice in firing the A/T rifle to be carried out with the same motion as if the man were shooting full charge ammunition.
We should like to see the results of further trials.
D. of A..(A.3), 25. 5. 40, to See. O.B.
To note remarks by M.T. regarding accuracy in relation to this investigation.
Action.—Noted.
Forward to C.SAD. for information.
27


NO. 7,598                  See 8167                      SECRET.
24.7 40
1.03/0/17                         RIFLES.
110/1/3/1             Boys 0.55 inch.
110/1/14/1             Parker-Hale conveyors for sub-calibre firing.
F        Previous No. 6,783.
C.I.S.A., 11. 7. 40, to Sec. O.B. (re No. 6,016).
Twenty conveyors to the new designs have been submitted by C.S.D. for trial, and accuracy diagrams have been fired at 15 and 25 yards. As the standard of accuracy desired by Comdt. S.A.S. was not obtained at these ranges, trials at greater ranges were not attempted. These conveyors are a good fit in the chamber of a new rifle, but the " bores " are not concentric with the outside of the conveyor and vary from 0.002 to 0.012 inch in eccentricity. Where one conveyor was placed in the chamber in the same position a 5-round diagram of inch x ½ inch at 15 yards range was obtained, which goes to prove that the requisite accuracy is obtainable from. a 4-inch barrel, but we are doubtful if a concentricity of bore greater than that of the samples submitted for trial could be obtained in manufacture.
Thus it would appear that an accuracy figure of a 2-inch group at 15 yards is the best that can be expected from these conveyors.
One round, when feeding from the magazine, struck the barrel face and set up a burr at the muzzle of the conveyor, causing inaccuracy and key-holing with this round. The same thing might. occur as a result of ejection on to a hard floor.
Sixteen. conveyors have been forwarded to Comdt. S.A.S. for trial.

REPORT OF TRIAL.
Date, 10. 7. 40.            Gun.-No. A 5.            Ammunition.-I.C.I. Rim Fire, Mark I.
No. of conveyors used. - 20. (From 0.002 to 0.012 inch eccentric.)


ROUNDS FIRED.

RECTANGLE.

RANGE.

CONVEYORS USED.

REMARKS.

5

1.4 x 1.5

15

All 20 conveyors used once only.

 

5

2.0 x 1-2

15

,,

 

5

2.5 x 1-6

15

„                            ,3

 

5

1.5 x 1.4

15

1,

 

5

1.4x 2.0

15

One picked at random.

 

5

0.5 x 0.5

15

Same one as above.

Conveyor set in barrel at same position for each shot.

5

0.5x 0.75

15

Second one picked at random.

As .above.

5

Not taken.

25

5 conveyors all 0.005 inch eccentric.

4 hits on target.

5

,,

25

5                      at random.

2

5

1.0x 5.75

25

5                      all 0.005 inch eccentric.

 

5

3-5x 1.5

25

5                      at random.

1 B.S.O.       Due to nose of con-
veyor hitting barrel.                  

5

1.1 x 1.3

25

1 conveyor 0007 inch eccentric.

Conveyor set in barrel at same position for each shot.

5

2.0x 2.3

25

5 conveyors least eccentric.

 

Advanced Action, 19. 7. 40.
Forward to D. of A.
The accuracy obtained with these conveyors shows little improvement on that reported in Proc. No. 6,016.
In normal production it should, in the opinion of the Board, be possible to work to a maximum eccentricity of bore of about 0.0075 inch, even so the size of the rectangle at 15 yards will not be appreciably less than 2 inches square.
By selective loading, i.e., loading each round in the chamber so that the eccentricity is either up or down, a considerably reduced rectangle should be obtained ; and if it is decided to supply these conveyors for training purposes, it is suggested that this pro­cedure should be adopted. To reduce the work carried out by C.I.A., it is suggested that the determination of the best position for each conveyor should be carried out by units, that the " up " position on each conveyor should be marked and that they should subsequently be loaded into magazines in the correct relative position.
Trials are being continued by Comdt. S.A.S., and he has been asked to test this system and report by telephone.
Forward to C.I.A., C.S.D., C.I.S.A. and Comdt. S.A.S. for information.

Action.- 'The Board confirm Advanced Action taken on 19. 7. 40.



No 8,167
21.840
103/0/17                  RIFLES.
110/1/3/1                  Boys 0.55 inch.
1104/14/1                 Parker-Hale conveyors for sub-calibre firing.
LSAE42
F


SECRET

Previous No. 7,598.


S. of E. (Pendine), 3. 8. 40, to See. O.B.

  1. The object of this trial was to determine whether the standard of accuracy obtained was satisfactory :—

(a). With no " selective" loading,
(in. With " selective " loading,
i.e., loading conveyors always in the same relative position in the maga­zine, so that the same given point on the circumference always came uppermost in the breech.
In regard to (a), 0.C. Hythe Wing S.A.S. confirms that the standard of accuracy obtained in the trial is acceptable, and in these circumstances it does not appear necessary to introduce (b) .
In any case, it Would be undesirable to introduce further complication in training in respect of selective loading, for which conveyors would presumably have to be " matched " by trial and error on the range.

  1. The question of training expedients to supplement full charge firing with the 0-55 inch Boys has been the subject of much controversy since the rifle was introduced (S.A.C. Minute 1,628, .dated, 13. 1. 37, refers).

It is agreed that nothing can replace full charge firing. Even the aluminium bullets for use on classification ranges would not obviate the necessity for completing training with full charge firing.
Supply questions involving wear of barrels as well as provision of ammunition can hardly be disregarded.
Text Box:  In regard to barrel wear, the following gauging records of guns used in this estab­lishment, and since exchanged, may be of interest :-
Barrel gauging.


Rifle \o.

Rounds fired.

Runs.

Rejects.

2715

1238

0.556

0.563

A.50

1689

0.553

0.559

A.5609

852

0.551

0'555

It is not possible to give a reliable indication of the effect of the above records of wear on M.V., since delay was experienced in obtaining reliable cordite W Mark I and cordite W Mark IT ammunition for control purposes, but it may be accepted that 1000-1500 rounds with cordite W Mark I or cordite W Mark II ammunition will result in barrel wear, which will appreciably affect performance.
Report by E.L.O. S.A.S., dated 29. 7. 40.
Information.
Received sixteen 0-55 inch / 0.22 conveyors by Parker-Hale for trial.
The Board instructed by telephone that great care should be taken to test the con­veyor in various relative positions in the barrel.


Method.
The C.O. Hythe Wing agreed to accept any reasonable grouping capacity. The following trials, therefore. were staged, using four rifles
Trial 1.      Stationary target, 200/25.
Grouping at 10 yards.
15 „
25
Expert firers.
Trial 11. Stationary tank target, 1/30th scale.
Application at 10 yards.
15 „,,
    20 „
25 „
Expert firers.
Trial Ill. Repeat trial II at moving target. 1/30th scale.
Expert firers.
Trial TV. Repeat trials II and III with troops.
The trials to be conducted in a miniature range.
This was a covered range and climatics can be ignored.
The troops employed were tyro soldiers, having no knowledge of the weapon beyond elementary aiming.
Check groups were fired by Officer and N.C.O. instructors in trial IV.
Results


NO. 8,167 (contd.)
'2 1 .8.40
Results.
Trial I.-450 rounds were fired, each group being of five rounds. The grouping capacity was as follows :—
10 yards. A 1 inch group should be held.
            15 „                  A 1.5-inch group should be held.
            20 „         A 3-inch group should be obtained.
            25 „                  A group of 3.5 inches to 4 inches and over becomes the rule.
Trial IL—The greater difficulty of aim did not affect efficiency. Groups as for trial I.
Trial III.—The grouping capacity was maintained and the practice satisfactory from the instructional standpoint.
Trial IV.—The groups naturally included more wide shots, but the sequence of instruction could be followed and valuable lessons illustrated by firing.
The conveyors bore numbers but no difference was found as between one or the other. No effect was particularly noticeable due to position.
The rifles did not vary appreciably.
The conveyors were easy to load and unload and did not show any serious fouling. Careful examination did not disclose any damage.
Conclusions.
The conveyors are a good fit in the rifle.
They are accurate within the limits required for 1/30th scale target practice up to 20 yards.
They enable miniature range practice to be conducted with any rifle without extra apparatus, or special preparation.
They are easy to operate and maintain.
Recommendations by 0.0. Hythe Wing S.A.S.

  1. The standard of accuracy, while none too high, is acceptable.
  2. The apparatus is well made and excellent as a training device for rainy days and winter evenings, if accuracy of aim alone is considered, and fulfils a peace-time requirement.
  3. This device has no war value. The conveyors are obviously well made and must have taken material, time and money, better employed for another purpose. They cannot replace in value one round of ball ammunition.
  4. I recommend the dropping of the idea in war and concentration on the provision of the real thing, which is the only way .to train now. I cannot see that any con­structional value can come from a diversion of effort, either industrially or in units at the present time.

Comdt. Infantry Schools, 31. 7. 40, to D.S. of E.
I have not been able to see these trials and so cannot speak with personal experience. I concur, however, in the recommendation contained in para. 4 of 0.0. Hythe Wing S.A.S. minute above.
Note by Secretary.—An advance copy of the above firing report, together with the recommendations of the C.O. Hythe Wing, was forwarded to D. of A. on 6. 8. 40.
Action.—Forward to D. of A.
The Board note that the accuracy achieved is acceptable. To maintain this accuracy in supply close tolerances will have to be worked to, but this should be by no means impracticable.
Forward to O. S.D. , C . S. A., C.O. Hythe Wing S.A.S. and S. of E. (Pendine) for information.

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