My question is, if I turn the bow poundage down to the lower end of its range, how badly will that affect the specs and the bow's tune? Am I looking at minor tweaks, or major start-over?
Xman or others with experience, any insight? It's a Drenalin if that helps.
Thanks guys BS'er
I had a matching pair of Brownings that were probably about eight years old at the time, and both had been replaced in my active bow lineup by a later Mathews, so were only back-up bows.
I was barely able to hold the bow out at the distance to start drawing, and had no strength in the bow arm to resist the draw. Figured at first I would be just using the old bows as an exercise device to regain strength. Wasn't sure about shooting one turned down that far.
After turning down that first one a turn at a time on each limb until I could finally draw it, I measured the draw weight at 27#. I pulled it indoors for a couple weeks until I got bored with that and staggered into the back yard to find out if it would shoot.
The draw had felt fine and smooth, so it didn't surprise me too much that the bow shot just fine at that weight reduction. I did encounter one problem after a hew shots. I got a little sloppy on the release, and the string jumped the groove on the pulley as it came back to the rest position! Thought about taking it back in the house to press it and repair, but decided to see if I could just put it back in place with my bare fingers. It wasn't difficult to do. Hardly any weight left on the string at rest when turned down that drastically.
The shots were smooth and quiet, no rattling of loose parts. The limbs stayed at the same reduced weight. I had amrked the limb bolt positions with a sharpie to check on them in case the reduced tension might not be enough to hold them in place.
Performance was, of course, very slow, but otherwise seemed completely normal.
I shot it out in the yard at every opportunity after that, while still also using it indoors as a training device. Gradually restored the draw weight a turn at a time, until it was back up to 40# by season opener. Still wasn't in shape to do much actual hunting, but equipped myself so that in case a really careless deer might wander by my ground blind at close range and pause too long, I could maybe get it done. By that time I had also cranked down my Mathews LX that performed even better at the reduced weight, from 70# to 40#, and clocked it at 200 fps with my 450 grain hunting arrows, so I had confidence that it would be enough performance to yield a quick kill if I could do my part and place it well.
I don't recall measuring the bows for any changes in stats other than draw weights as I did the whole experiment and rehabbed. If there were any changes in statistics, it was not noticeable in shooting. I can't see how the ATA or BH would be changed by the draw weight reduction on a single-cam. The bus cable is still the same length and determines both those measurements.
I would expect that the Drenalin would behave in a similar fashion to my LX and another Mathews I picked up used when my LX was stolen while still cranked down to about 45#, a Legacy 70# that I also cranked down to about 40# to continue my recovery. No problems at all with any of those bows in shooting. The Browning was the only ones turned down to the extremes of weight reduction, but both it and its twin, and three Mathews, all 70# bows, ended up being turned down to the 40# level at some point. No ill effects on any of them. I was shooting Easton 340's at 70#, which were just a tad stiff at my 28" draw, but I always liked an arrow a tad on the stiff side for my finger release and good BH performance under hunting conditions. I could detect very little difference in tune due to the spine being so much further above that required for the reduced draw weights. It's very hard to over-spine with any reasonably modern compound with a full-centershot riser.
I did of course have to make considerable changes in pin height, but only minor changes in windage to compensate for the draw weight changes as they occurred. And I was shooting fingers. With a release, you should see even less difference with being overspined, as fingers shooters normally have a bit more side pressure at release.
Only caution I would advise for anyone wanting to reduce the draw weight beyond the manufacturer recommendations, is to examine your limb bolt situation and be sure you will not back them out so far as to run out of threads. Mine all had plenty of threaded length so that they were still engaged for the full length of the nut at the lowest weight. I suspect that condition would be typical, but might not be universal.
The scary aspect of shooting anything when beyond manufacturer spec's is pretty much negated in this case by the fact that there is such a great reduction in the pressures involved at every aspect when the weight is reduced. Once you've replaced your string in the pulley groove with your fingers, easily, without using a press, you gain more confidence that the whole machine will hold together 8^).
Of course all my bows were used ones I had purchased after they were experienced, and there were no warranty issue to contend with.
I would also add that the often repeated advice about the loss of efficiency having a profound effect on performance when the bow is shot reduced weights, is, IMO, outdated. It was probably true back in the early compound era a couple of generations ago, when the limbs were heavier and longer, the hardware heavier and we used steel cables. Now, all the hardware has been so reduced in weight and drag, that the reduced draw weight has very little effect on efficiency. Performance will be reduced when shooting a 70# bow turned down to 40#, but it will still be very close to the performance you'd get from the same bow manufactured with a 40# maximum draw, shooting the same arrow.
Harder to edit them effectively, but I'll work on that 8^)
THANKS!
And Russ, I enjoyed your post/book. Haha
Sound practical? Feel free to tell me if I'm crazy.
Now to PM Mr. Schwister...
Barely got to shoot it. I certainly don't mind - even enjoy -broad head tuning, but I am not at the level of a tech by any means. Don't even own a press.
Any tips on how to SAFELY back out the limb bolts without risking going too far?
I now shoot at 60lbs, and anything above 60 will cause pain and unacceptable reduction in practice shots. But the single most damaging side affect is my reduced ability to draw after long sits in below freezing weather. So keep that in mind.
Based on my experience of having dealt with this situation for over 10 years now, the odds will be far more likely than not you will have to adjust your set up as your shooting form will likely be affected by your shoulder issue.
You have my sympathy and I wish you best of luck.