Just a few corrections to your post Mitch:
Rowland stated in his testimony that he was about 150 feet away. from the man he saw holding the rifle. It is an incredibly accurate estimation. Not sure where you're getting 300 ft from.
300 feet comes from Google Maps. The Rowlands are very specific as to their location. Google maps says that their position is about 280 feet from the column of windows in the SW corner of the TSBD; while the 6th floor window sill is about 65' above ground. Not sure how that Pythagoruses out, but the result should round to about 300 feet.
Rowland is unequivocal that he had an excellent view of the rifle and recognised it as a type he had previously used.
"Deer rifle" is pretty generic. Most deer hunters I know seem to prefer lever guns for the task, but 'deer rifle' is a pretty generic term for a bolt action rifle. ".30-06" is a cartridge, rather than a type of rifle.
In his WC statement Rowland states that he doesn't remember saying the man with the rifle was stood 15 ft inside the building and seems confused as to why that's in the affidavit. He clarifies his observation in his WC testimony:
Mr. ROWLAND - He wasn't next to the window, but he wasn't very far back. I would say 3 to 5 feet back from the window.
Not 15ft in the building. 3-5 ft, and Rowland also states the sun was shining on the rifle making it easier to see. The comment about his wife's testimony seems strange.
He signed the affidavit as being "true and correct to the best of my knowledge and belief."
A few days later, he executed another statement to the FBI wherein he said that the man with the rifle was 12-15 feet inside the window.
I think Rowland is the most impressive Dealey Plaza witness of all those who testified regarding the assassination. His memory and attention to detail are quite mind blowing. He saw the rifle clearly and described it clearly.
Sometimes, highly detailed memories are red flags, and ought to be treated with some skepticism.
As I said, read his testimony --and his wife's-- as to his background, and you'll come up with a different impression of the guy. If nothing else, count up how many jobs he's held in the year leading up to Mrs Rowland's WC deposition. I get:
West Foods (Salem Oregon)
Exchange Lumber (Salem)
Myron Frank (Salem)
Pizza Inn (Dallas)
Sanger Harris (Dallas)
Civic Reading Club (Dallas)
P.F. Collier (Dallas)
Life Circulation (Dallas)
The Rowlands were married May 16,1963. The next day they moved to Oregon, where they stayed until September. In their Nov 22, 1963 DCSD affidavits, the list 3026 Hammerly in Dallas. In their Mar 10, 1964 WC depositions, they said that they lived at 1131 Phinney, also in Dallas. Then there's the Feb 19, 1964 DCSD Det. Rose report regarding trying to find the Rowlands' whereabouts. Rose finds out that that the Rowlands no longer live at the Hammerly address (which belonged to Barbara's mother). Rowland's in-laws don't know where the young couple moved to. He checks with Adamson high school, where the Rowlands attended high school in the fall of '63. School records indicate that the Arnold and Barbara live at 809 S Marsalis, which turns out to be a "fictitious address,'" as Detective Rose notes. He's able to get a PO box from the Rowland in-laws, and finds that Rowland lists an address at 4114 Lakehurst Ct. However, the Rowlands only lived on Lakehurst from September 11, 1963 to November 14, 1963. Interestingly, that particular PO box was rented to the Rowlands on November 21, 1963, a week after the Rowlands vacated the Lakehurst address used to rent the box.
These aren't people with particularly stable lives. There's usually a reason for that. It's often not a good one.
Or, you can figure out if he's actually graduated from high school --there seems to be some question about that.
Mr. SPECTER - When did you graduate from high school?
Mr. ROWLAND - June 1963.
However....
Mr. BELIN. Is your husband a high school graduate or not?
Mrs. ROWLAND. No.
[...]
Mr. BELIN. Do you know how far your husband got through school?
Mrs. ROWLAND. Well, his credits are all mixed up. I think he lacks one or two semesters.
Mr. BELIN. Of completing high school?
Mrs. ROWLAND. Yes.
And there's some differences about grades:
Mr. SPECTER - Mr. Rowland, what was the quality of your grades in high school?
Mr. ROWLAND - Well, up until my senior year they were 4.0 straight A's, in my senior year I got a couple of B's.
Mr. BELIN. Do you know about what his grades were?
Mrs. ROWLAND. Varied.
Mr. BELIN. What do you mean by that?
Mrs. ROWLAND. He made A's and B's in some subjects, and he made C's and D's, I think, in other subjects.
Mr. BELIN. Was this before .you were married?
Mrs. ROWLAND. Yes. He says he has an A average, but I don't believe him.
Mr. BELIN. Why? Did he tell you that?
Mrs. ROWLAND. Yes. He told me that, because I saw a few of his report cards.
Mr. BELIN. Pardon?
Mrs. ROWLAND. I saw a few of his report cards and they weren't all A's.
Not to beat on him too hard, we have this exchange:
Mr. SPECTER - Was the sound of the fire different from the first and second sounds you described?
Mr. ROWLAND - No, that is just it. It did not sound as though there was any return fire in that sense.
Mr. SPECTER - What do you mean by return fire?
Mr. ROWLAND - That anyone fired back. You know, anyone in the procession such as our detectives or Secret Service men fired back at anything else. It gave the report of a rifle which most of the Secret Service men don't carry in a holster although I am sure they had some in the cars but the following two shots were the same report being of the same intensity, I state, because from a different position I know that the same rifle is not going to make the same sound in two different positions especially in a position such as it was, because of the ricocheting of sound and echo effects.
Mr. SPECTER - What is your basis for saying that, Mr. Rowland, that the rifle would not make the same sound in two different positions?
Mr. ROWLAND - This is due to a long study of sound and study of echo effects.
Mr. SPECTER - When had you conducted that study?
Mr. ROWLAND - In physics in the past 3 years.
Mr. SPECTER - Have you read any special books on that subject?
Mr. ROWLAND - Quite a few.
Mr. SPECTER - Do you recollect any of the titles and authors?
Mr. ROWLAND - No; I do not.
Mr. SPECTER - Did you take any special courses which would give you insight into that subject matter?
Mr. ROWLAND - This was more or less on my own initiative. The instructor gave me help and aided me when I requested this during my off periods of class.
Mr. SPECTER - What instructor was that?
Mr. ROWLAND - His name was Foster.
Mr. SPECTER - Do you recall his first name?
Mr. ROWLAND - Sam.
[...]
Senator COOPER - You said earlier that you had been much interested in and pursued studies in sounds, I believe?
Mr. ROWLAND - I have studied quite a bit of electronics, sound. Math and science is what I like.
Senator COOPER - You said you had read books on this subject. Did you ever conduct any experiments yourself?
Mr. ROWLAND - Yes; in the form of--there is a theory that sound is a basis of a transmitter and a receiver, that you have to have a receiver to have sound. There is a theory that if a tree falls down in the middle of a forest and there is nobody around where they can hear it, there is no sound.
Well, I have conducted experiments on this, and I--it is very interesting, very fascinating, but you can't prove it or you can't disprove it because if you have got a microphone there you have got a receiver.
Senator COOPER - Did you ever conduct any experiments with rifles, firing a rifle in relation to sound?
Mr. ROWLAND - Yes; in a firing range.
Senator COOPER - Beg pardon?
Mr. ROWLAND - Firing range.
Senator COOPER - Yes.
Mr. ROWLAND - I did conduct a few experiments. One of them was firing a bullet over water; you know, we were using a set of wood blocks to fire into, so we had a big vat of water that we were firing over, and we had several different articles and composition floating on the water, trying to measure the effect of the sound wave upon that. Such as this we did conduct.
Senator COOPER - I think you did say that when you heard the first report that you considered it to be a rifle shot?
And, finally, this:
Mrs. ROWLAND. At times my husband is prone to exaggerate. Does that answer it?
Mr. BELIN. I think it does.
Is there anything else you want to add to that, or not?
Mrs. ROWLAND. Usually his exaggerations are not concerned with anything other than himself. They are usually to boast his ego. They usually say that he is really smarter than he is, or he is a better salesman than he is, something like that.