"Bastard musket bore?" (My second dumb question today...)

[Tarn_Helm]

What does the phrase "bastard musket bore" mean, or refer to, in the context of this passage below (with red font added by me)?

"The musketeer should carry a 'good fixed musket,' not under bastard musket bore, not less than three feet, nine inches, nor more than four feet three inches in length, a priming wire, scourer, and mould, a sword, rest, bandoleers, one pound of powder, twenty bullets, and two fathoms of match."

Please see the pdf linked below, page 7 (or page 180 of the original), for the complete context:

https://tile.loc.gov/storage-services/service/ll/usrep/usrep307/usrep307174/usrep307174.pdf

[Tarn_Helm]

I discovered an amazing thing called Google today.

It led me to this https://www.oocities.org/yosemite/ca.../firearms.html . . .

. . . which led me to this . . .

"The bastard musket was shorter, lighter version of the musket with a bore size in between that of the caliver and the musket. The bastard musket used either a trigger lever or conventional trigger to operate the matchlock mechanism."

So, a bastard musket is a musket that is between "caliver" and "musket" in size, as depicted and described on this very old webpage.

[Wheellock]

Likely high 60 to 72 caliber. I couldn't find anything concrete.

[Tarn_Helm]

Likely high 60 to 72 caliber. I couldn't find anything concrete.

At first I was curious about the name.

After getting my answer and thinking about it for a minute, I then became curious about it in more technical terms, which your post addressed.

So, thank you.