So, here’s the report. Skip to the end if you’re only interested in my recommendations for larp archery with round-headed IDV arrows.
We measured four types of bow using IDV round-headed arrows.
Draw length was measured from the cleft of the nock to the “back” of the bow (which is the part of the bow that faces the target). The IDV round-headed arrows have a maximum draw length of 710mm, or 28". This is the length to the beginning of the “IDV” sticker on the shaft near the head of the arrow. Three of the bows could draw to this length. Bow B could only draw to 24".
We used a bow scale and measuring tape for all measurements, apart from the effective range which we just paced out as it was only for interest. We measured effective range by firing the arrows at roughly a 45 degree angle and at their full draw.
[size=130]Measurements[/size]
Bow A - IDV 140cm 27lb @ 28"
Official draw weight: 27lb @ 28"
Measured draw weight: 27 lb @ 28"
Effective range at full draw: 42m
Bow B - Squire bow small 96cm
Official draw weight: 25lb @ 26"
Measured draw weight: 26.5 lb @ 24"
Effective range at full draw: 23m
Bow C - Barnett Lil’ Sioux
Official draw weight: unknown
Measured draw weight: 34lb @ 28"
Effective range at full draw: 50m
Bow D - Martin Archery (model unknown)
Official draw weight: 25lb
Measured draw weight: 26.5lb @ 28"
Effective range at full draw: not measured
[size=130]Testing[/size]
We shot the bows at people at ranges of 20m, 10m and 5m and asked the targets to rate whether the impacts were good or too hard. Faces were not targeted, but targets were asked to estimate whether the impact would have been acceptable if it had hit their face. This approach tended to lean targets towards saying blows were too hard more readily than they might otherwise, so these results could be considered conservative.
At each range bows A, B, and D were relatively similar. Bow C was stronger, and had to be drawn much less to result in an acceptable impact. Bow C was only tested at 20m range, after which we decided not to continue testing it because a) it would involve extra work to determine its acceptable draw length as it differed a lot from the other bows and b) it exceeded the usual international maximum larp bow draw weight of 30lb @ 28" inches so we considered it unlikely that GMs would wish to have it at games. It should be noted that this bow had previously been found acceptable at an archery training event, but that was without the benefit of a bow scale to give an objective measure of draw weight.
At 20m range a full draw generally resulted in acceptable impacts (apart from bow C).
At 10m range a full draw was too hard. A draw of about 430mm or 17" was acceptable across bows A, B and D.
At 5m range a draw of 430mm was too hard. A draw of about 390mm or 15" was acceptable across bows A, B and D.
We also shot at a pair of plastic-lensed glasses mounted on a polystyrene head at a range of 5m, with a draw of about 400mm. The shots that landed on the glasses did not appear to damage them. Two slight dents were made in the polystyrene head where the glasses were forced against it.
[size=130]My recommendations[/size]
These are only my personal recommendations based on this test, and are specific to the IDV round-headed arrows as those are the only arrows we tested.
Maximum 27lb draw bows - I recommend bows with a maximum draw weight of 27lb at full draw for use with round-headed IDV arrows. While this is less than the usual international standard of 30lb @ 28", that standard was developed in the UK with the use of flat-headed arrows with open-cell foam padding, which fly slower and hit softer. Bows with a maximum draw weight of 27lbs are readily available to us, and this weight was sufficient to achieve acceptable ranges in the test.
Use minimum draw length for range - I recommend that archers only use the draw necessary to reach their target at the given range and to target the middle of their body with accuracy. There is a temptation to draw longer in order to give a faster shot, however our tests found that these faster shots were often unacceptably hard. Our targets also frequently mentioned that having things flying at them at high speed was alarming, so have some empathy for the targets.
Mark draw lengths - I recommend that archers mark their IDV round-headed arrows at distances 390mm and 430mm from the inside of the nock, and practice shooting at targets at measured ranges of 5m and 10m using these marks, at 20m range using full draw, and at intermediate ranges using intermediate draw lengths. This will help to calibrate your draw to acceptable lengths for the range. Use a human target at first so they can inform you if the impact was too hard, and you can reduce your draw accordingly.
Only wear plastic-lensed glasses - I support Cameron Burns’ recommendation that only plastic-lensed glasses be worn at larps with live combat. This is not just for safety in archery, but also for foam weapon combat and to prevent broken glass underfoot. Cameron says that most prescription glasses these days are plastic-lensed, as they are lighter and more durable.
Thanks again to everyone who helped with the test.
Ryan